diff --git a/Dockerfile b/Dockerfile
index b5c8904..aab54a8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -200,6 +200,16 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     && make install \
     && ldconfig \
     && rm -rf /tmp/hackrf \
+    # Install radiosonde_auto_rx (weather balloon decoder)
+    && cd /tmp \
+    && git clone --depth 1 https://github.com/projecthorus/radiosonde_auto_rx.git \
+    && cd radiosonde_auto_rx/auto_rx \
+    && pip install --no-cache-dir -r requirements.txt \
+    && mkdir -p /opt/radiosonde_auto_rx/auto_rx \
+    && cp -r . /opt/radiosonde_auto_rx/auto_rx/ \
+    && chmod +x /opt/radiosonde_auto_rx/auto_rx/auto_rx.py \
+    && cd /tmp \
+    && rm -rf /tmp/radiosonde_auto_rx \
     # Build rtlamr (utility meter decoder - requires Go)
     && cd /tmp \
     && curl -fsSL "https://go.dev/dl/go1.22.5.linux-$(dpkg --print-architecture).tar.gz" | tar -C /usr/local -xz \
@@ -246,7 +256,7 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY . .
 
 # Create data directory for persistence
-RUN mkdir -p /app/data /app/data/weather_sat
+RUN mkdir -p /app/data /app/data/weather_sat /app/data/radiosonde/logs
 
 # Expose web interface port
 EXPOSE 5050
diff --git a/app.py b/app.py
index b74410b..9fedb75 100644
--- a/app.py
+++ b/app.py
@@ -198,6 +198,11 @@ tscm_lock = threading.Lock()
 subghz_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
 subghz_lock = threading.Lock()
 
+# Radiosonde weather balloon tracking
+radiosonde_process = None
+radiosonde_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
+radiosonde_lock = threading.Lock()
+
 # CW/Morse code decoder
 morse_process = None
 morse_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
@@ -766,6 +771,7 @@ def health_check() -> Response:
             'wifi': wifi_active,
             'bluetooth': bt_active,
             'dsc': dsc_process is not None and (dsc_process.poll() is None if dsc_process else False),
+            'radiosonde': radiosonde_process is not None and (radiosonde_process.poll() is None if radiosonde_process else False),
             'morse': morse_process is not None and (morse_process.poll() is None if morse_process else False),
             'subghz': _get_subghz_active(),
         },
@@ -784,12 +790,13 @@ def health_check() -> Response:
 def kill_all() -> Response:
     """Kill all decoder, WiFi, and Bluetooth processes."""
     global current_process, sensor_process, wifi_process, adsb_process, ais_process, acars_process
-    global vdl2_process, morse_process
+    global vdl2_process, morse_process, radiosonde_process
     global aprs_process, aprs_rtl_process, dsc_process, dsc_rtl_process, bt_process
 
-    # Import adsb and ais modules to reset their state
+    # Import modules to reset their state
     from routes import adsb as adsb_module
     from routes import ais as ais_module
+    from routes import radiosonde as radiosonde_module
     from utils.bluetooth import reset_bluetooth_scanner
 
     killed = []
@@ -799,7 +806,8 @@ def kill_all() -> Response:
         'dump1090', 'acarsdec', 'dumpvdl2', 'direwolf', 'AIS-catcher',
         'hcitool', 'bluetoothctl', 'satdump',
         'rtl_tcp', 'rtl_power', 'rtlamr', 'ffmpeg',
-        'hackrf_transfer', 'hackrf_sweep'
+        'hackrf_transfer', 'hackrf_sweep',
+        'auto_rx'
     ]
 
     for proc in processes_to_kill:
@@ -829,6 +837,11 @@ def kill_all() -> Response:
         ais_process = None
         ais_module.ais_running = False
 
+    # Reset Radiosonde state
+    with radiosonde_lock:
+        radiosonde_process = None
+        radiosonde_module.radiosonde_running = False
+
     # Reset ACARS state
     with acars_lock:
         acars_process = None
diff --git a/config.py b/config.py
index 76635b8..434d2b1 100644
--- a/config.py
+++ b/config.py
@@ -355,6 +355,12 @@ SUBGHZ_MAX_TX_DURATION = _get_env_int('SUBGHZ_MAX_TX_DURATION', 10)
 SUBGHZ_SWEEP_START_MHZ = _get_env_float('SUBGHZ_SWEEP_START', 300.0)
 SUBGHZ_SWEEP_END_MHZ = _get_env_float('SUBGHZ_SWEEP_END', 928.0)
 
+# Radiosonde settings
+RADIOSONDE_FREQ_MIN = _get_env_float('RADIOSONDE_FREQ_MIN', 400.0)
+RADIOSONDE_FREQ_MAX = _get_env_float('RADIOSONDE_FREQ_MAX', 406.0)
+RADIOSONDE_DEFAULT_GAIN = _get_env_float('RADIOSONDE_GAIN', 40.0)
+RADIOSONDE_UDP_PORT = _get_env_int('RADIOSONDE_UDP_PORT', 55673)
+
 # Update checking
 GITHUB_REPO = _get_env('GITHUB_REPO', 'smittix/intercept')
 UPDATE_CHECK_ENABLED = _get_env_bool('UPDATE_CHECK_ENABLED', True)
diff --git a/routes/__init__.py b/routes/__init__.py
index 3a00b91..61c1ba6 100644
--- a/routes/__init__.py
+++ b/routes/__init__.py
@@ -19,6 +19,7 @@ def register_blueprints(app):
     from .morse import morse_bp
     from .offline import offline_bp
     from .pager import pager_bp
+    from .radiosonde import radiosonde_bp
     from .recordings import recordings_bp
     from .rtlamr import rtlamr_bp
     from .satellite import satellite_bp
@@ -76,6 +77,7 @@ def register_blueprints(app):
     app.register_blueprint(signalid_bp)  # External signal ID enrichment
     app.register_blueprint(wefax_bp)  # WeFax HF weather fax decoder
     app.register_blueprint(morse_bp)  # CW/Morse code decoder
+    app.register_blueprint(radiosonde_bp)  # Radiosonde weather balloon tracking
     app.register_blueprint(system_bp)  # System health monitoring
 
     # Initialize TSCM state with queue and lock from app
diff --git a/routes/radiosonde.py b/routes/radiosonde.py
new file mode 100644
index 0000000..2fb1ae0
--- /dev/null
+++ b/routes/radiosonde.py
@@ -0,0 +1,547 @@
+"""Radiosonde weather balloon tracking routes.
+
+Uses radiosonde_auto_rx to automatically scan for and decode radiosonde
+telemetry (position, altitude, temperature, humidity, pressure) on the
+400-406 MHz band.  Telemetry arrives as JSON over UDP.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import queue
+import shutil
+import socket
+import subprocess
+import threading
+import time
+from typing import Any
+
+from flask import Blueprint, Response, jsonify, request
+
+import app as app_module
+from utils.constants import (
+    MAX_RADIOSONDE_AGE_SECONDS,
+    PROCESS_TERMINATE_TIMEOUT,
+    RADIOSONDE_TERMINATE_TIMEOUT,
+    RADIOSONDE_UDP_PORT,
+    SSE_KEEPALIVE_INTERVAL,
+    SSE_QUEUE_TIMEOUT,
+)
+from utils.logging import get_logger
+from utils.sdr import SDRFactory, SDRType
+from utils.sse import sse_stream_fanout
+from utils.validation import validate_device_index, validate_gain
+
+logger = get_logger('intercept.radiosonde')
+
+radiosonde_bp = Blueprint('radiosonde', __name__, url_prefix='/radiosonde')
+
+# Track radiosonde state
+radiosonde_running = False
+radiosonde_active_device: int | None = None
+radiosonde_active_sdr_type: str | None = None
+
+# Active balloon data: serial -> telemetry dict
+radiosonde_balloons: dict[str, dict[str, Any]] = {}
+_balloons_lock = threading.Lock()
+
+# UDP listener socket reference (so /stop can close it)
+_udp_socket: socket.socket | None = None
+
+# Common installation paths for radiosonde_auto_rx
+AUTO_RX_PATHS = [
+    '/opt/radiosonde_auto_rx/auto_rx/auto_rx.py',
+    '/usr/local/bin/radiosonde_auto_rx',
+    '/opt/auto_rx/auto_rx.py',
+]
+
+
+def find_auto_rx() -> str | None:
+    """Find radiosonde_auto_rx script/binary."""
+    # Check PATH first
+    path = shutil.which('radiosonde_auto_rx')
+    if path:
+        return path
+    # Check common locations
+    for p in AUTO_RX_PATHS:
+        if os.path.isfile(p) and os.access(p, os.X_OK):
+            return p
+    # Check for Python script (not executable but runnable)
+    for p in AUTO_RX_PATHS:
+        if os.path.isfile(p):
+            return p
+    return None
+
+
+def generate_station_cfg(
+    freq_min: float = 400.0,
+    freq_max: float = 406.0,
+    gain: float = 40.0,
+    device_index: int = 0,
+    ppm: int = 0,
+    bias_t: bool = False,
+    udp_port: int = RADIOSONDE_UDP_PORT,
+) -> str:
+    """Generate a station.cfg for radiosonde_auto_rx and return the file path."""
+    cfg_dir = os.path.join('data', 'radiosonde')
+    os.makedirs(cfg_dir, exist_ok=True)
+    cfg_path = os.path.join(cfg_dir, 'station.cfg')
+
+    # Minimal station.cfg that auto_rx needs
+    cfg = f"""# Auto-generated by INTERCEPT for radiosonde_auto_rx
+[search_params]
+min_freq = {freq_min}
+max_freq = {freq_max}
+rx_timeout = 180
+whitelist = []
+blacklist = []
+greylist = []
+
+[sdr]
+sdr_type = rtlsdr
+rtlsdr_device_idx = {device_index}
+rtlsdr_gain = {gain}
+rtlsdr_ppm = {ppm}
+rtlsdr_bias = {str(bias_t).lower()}
+
+[habitat]
+upload_enabled = False
+
+[aprs]
+upload_enabled = False
+
+[sondehub]
+upload_enabled = False
+
+[positioning]
+station_lat = 0.0
+station_lon = 0.0
+station_alt = 0.0
+
+[logging]
+per_sonde_log = True
+log_directory = ./data/radiosonde/logs
+
+[advanced]
+web_host = 127.0.0.1
+web_port = 0
+udp_broadcast_port = {udp_port}
+"""
+
+    with open(cfg_path, 'w') as f:
+        f.write(cfg)
+
+    logger.info(f"Generated station.cfg at {cfg_path}")
+    return cfg_path
+
+
+def parse_radiosonde_udp(udp_port: int) -> None:
+    """Thread function: listen for radiosonde_auto_rx UDP JSON telemetry."""
+    global radiosonde_running, _udp_socket
+
+    logger.info(f"Radiosonde UDP listener started on port {udp_port}")
+
+    try:
+        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        sock.bind(('0.0.0.0', udp_port))
+        sock.settimeout(2.0)
+        _udp_socket = sock
+    except OSError as e:
+        logger.error(f"Failed to bind UDP port {udp_port}: {e}")
+        return
+
+    while radiosonde_running:
+        try:
+            data, _addr = sock.recvfrom(4096)
+        except socket.timeout:
+            # Clean up stale balloons
+            _cleanup_stale_balloons()
+            continue
+        except OSError:
+            break
+
+        try:
+            msg = json.loads(data.decode('utf-8', errors='ignore'))
+        except (json.JSONDecodeError, UnicodeDecodeError):
+            continue
+
+        balloon = _process_telemetry(msg)
+        if balloon:
+            serial = balloon.get('id', '')
+            if serial:
+                with _balloons_lock:
+                    radiosonde_balloons[serial] = balloon
+                try:
+                    app_module.radiosonde_queue.put_nowait({
+                        'type': 'balloon',
+                        **balloon,
+                    })
+                except queue.Full:
+                    pass
+
+    try:
+        sock.close()
+    except OSError:
+        pass
+    _udp_socket = None
+    logger.info("Radiosonde UDP listener stopped")
+
+
+def _process_telemetry(msg: dict) -> dict | None:
+    """Extract relevant fields from a radiosonde_auto_rx UDP telemetry packet."""
+    # auto_rx broadcasts packets with a 'type' field
+    # Telemetry packets have type 'payload_summary' or individual sonde data
+    serial = msg.get('id') or msg.get('serial')
+    if not serial:
+        return None
+
+    balloon: dict[str, Any] = {'id': str(serial)}
+
+    # Sonde type (RS41, RS92, DFM, M10, etc.)
+    if 'type' in msg:
+        balloon['sonde_type'] = msg['type']
+    if 'subtype' in msg:
+        balloon['sonde_type'] = msg['subtype']
+
+    # Timestamp
+    if 'datetime' in msg:
+        balloon['datetime'] = msg['datetime']
+
+    # Position
+    for key in ('lat', 'latitude'):
+        if key in msg:
+            try:
+                balloon['lat'] = float(msg[key])
+            except (ValueError, TypeError):
+                pass
+            break
+    for key in ('lon', 'longitude'):
+        if key in msg:
+            try:
+                balloon['lon'] = float(msg[key])
+            except (ValueError, TypeError):
+                pass
+            break
+
+    # Altitude (metres)
+    if 'alt' in msg:
+        try:
+            balloon['alt'] = float(msg['alt'])
+        except (ValueError, TypeError):
+            pass
+
+    # Meteorological data
+    for field in ('temp', 'humidity', 'pressure'):
+        if field in msg:
+            try:
+                balloon[field] = float(msg[field])
+            except (ValueError, TypeError):
+                pass
+
+    # Velocity
+    if 'vel_h' in msg:
+        try:
+            balloon['vel_h'] = float(msg['vel_h'])
+        except (ValueError, TypeError):
+            pass
+    if 'vel_v' in msg:
+        try:
+            balloon['vel_v'] = float(msg['vel_v'])
+        except (ValueError, TypeError):
+            pass
+    if 'heading' in msg:
+        try:
+            balloon['heading'] = float(msg['heading'])
+        except (ValueError, TypeError):
+            pass
+
+    # GPS satellites
+    if 'sats' in msg:
+        try:
+            balloon['sats'] = int(msg['sats'])
+        except (ValueError, TypeError):
+            pass
+
+    # Battery voltage
+    if 'batt' in msg:
+        try:
+            balloon['batt'] = float(msg['batt'])
+        except (ValueError, TypeError):
+            pass
+
+    # Frequency
+    if 'freq' in msg:
+        try:
+            balloon['freq'] = float(msg['freq'])
+        except (ValueError, TypeError):
+            pass
+
+    balloon['last_seen'] = time.time()
+    return balloon
+
+
+def _cleanup_stale_balloons() -> None:
+    """Remove balloons not seen within the retention window."""
+    now = time.time()
+    with _balloons_lock:
+        stale = [
+            k for k, v in radiosonde_balloons.items()
+            if now - v.get('last_seen', 0) > MAX_RADIOSONDE_AGE_SECONDS
+        ]
+        for k in stale:
+            del radiosonde_balloons[k]
+
+
+@radiosonde_bp.route('/tools')
+def check_tools():
+    """Check for radiosonde decoding tools and hardware."""
+    auto_rx_path = find_auto_rx()
+    devices = SDRFactory.detect_devices()
+    has_rtlsdr = any(d.sdr_type == SDRType.RTL_SDR for d in devices)
+
+    return jsonify({
+        'auto_rx': auto_rx_path is not None,
+        'auto_rx_path': auto_rx_path,
+        'has_rtlsdr': has_rtlsdr,
+        'device_count': len(devices),
+    })
+
+
+@radiosonde_bp.route('/status')
+def radiosonde_status():
+    """Get radiosonde tracking status."""
+    process_running = False
+    if app_module.radiosonde_process:
+        process_running = app_module.radiosonde_process.poll() is None
+
+    with _balloons_lock:
+        balloon_count = len(radiosonde_balloons)
+        balloons_snapshot = dict(radiosonde_balloons)
+
+    return jsonify({
+        'tracking_active': radiosonde_running,
+        'active_device': radiosonde_active_device,
+        'balloon_count': balloon_count,
+        'balloons': balloons_snapshot,
+        'queue_size': app_module.radiosonde_queue.qsize(),
+        'auto_rx_path': find_auto_rx(),
+        'process_running': process_running,
+    })
+
+
+@radiosonde_bp.route('/start', methods=['POST'])
+def start_radiosonde():
+    """Start radiosonde tracking."""
+    global radiosonde_running, radiosonde_active_device, radiosonde_active_sdr_type
+
+    with app_module.radiosonde_lock:
+        if radiosonde_running:
+            return jsonify({
+                'status': 'already_running',
+                'message': 'Radiosonde tracking already active',
+            }), 409
+
+    data = request.json or {}
+
+    # Validate inputs
+    try:
+        gain = float(validate_gain(data.get('gain', '40')))
+        device = validate_device_index(data.get('device', '0'))
+    except ValueError as e:
+        return jsonify({'status': 'error', 'message': str(e)}), 400
+
+    freq_min = data.get('freq_min', 400.0)
+    freq_max = data.get('freq_max', 406.0)
+    try:
+        freq_min = float(freq_min)
+        freq_max = float(freq_max)
+        if not (380.0 <= freq_min <= 410.0) or not (380.0 <= freq_max <= 410.0):
+            raise ValueError("Frequency out of range")
+        if freq_min >= freq_max:
+            raise ValueError("Min frequency must be less than max")
+    except (ValueError, TypeError) as e:
+        return jsonify({'status': 'error', 'message': f'Invalid frequency range: {e}'}), 400
+
+    bias_t = data.get('bias_t', False)
+    ppm = int(data.get('ppm', 0))
+
+    # Find auto_rx
+    auto_rx_path = find_auto_rx()
+    if not auto_rx_path:
+        return jsonify({
+            'status': 'error',
+            'message': 'radiosonde_auto_rx not found. Install from https://github.com/projecthorus/radiosonde_auto_rx',
+        }), 400
+
+    # Get SDR type
+    sdr_type_str = data.get('sdr_type', 'rtlsdr')
+
+    # Kill any existing process
+    if app_module.radiosonde_process:
+        try:
+            pgid = os.getpgid(app_module.radiosonde_process.pid)
+            os.killpg(pgid, 15)
+            app_module.radiosonde_process.wait(timeout=PROCESS_TERMINATE_TIMEOUT)
+        except (subprocess.TimeoutExpired, ProcessLookupError, OSError):
+            try:
+                pgid = os.getpgid(app_module.radiosonde_process.pid)
+                os.killpg(pgid, 9)
+            except (ProcessLookupError, OSError):
+                pass
+        app_module.radiosonde_process = None
+        logger.info("Killed existing radiosonde process")
+
+    # Claim SDR device
+    device_int = int(device)
+    error = app_module.claim_sdr_device(device_int, 'radiosonde', sdr_type_str)
+    if error:
+        return jsonify({
+            'status': 'error',
+            'error_type': 'DEVICE_BUSY',
+            'message': error,
+        }), 409
+
+    # Generate config
+    cfg_path = generate_station_cfg(
+        freq_min=freq_min,
+        freq_max=freq_max,
+        gain=gain,
+        device_index=device_int,
+        ppm=ppm,
+        bias_t=bias_t,
+    )
+
+    # Build command
+    cfg_dir = os.path.dirname(os.path.abspath(cfg_path))
+    if auto_rx_path.endswith('.py'):
+        cmd = ['python', auto_rx_path, '-c', cfg_dir]
+    else:
+        cmd = [auto_rx_path, '-c', cfg_dir]
+
+    try:
+        logger.info(f"Starting radiosonde_auto_rx: {' '.join(cmd)}")
+        app_module.radiosonde_process = subprocess.Popen(
+            cmd,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.PIPE,
+            start_new_session=True,
+        )
+
+        # Wait briefly for process to start
+        time.sleep(2.0)
+
+        if app_module.radiosonde_process.poll() is not None:
+            app_module.release_sdr_device(device_int, sdr_type_str)
+            stderr_output = ''
+            if app_module.radiosonde_process.stderr:
+                try:
+                    stderr_output = app_module.radiosonde_process.stderr.read().decode(
+                        'utf-8', errors='ignore'
+                    ).strip()
+                except Exception:
+                    pass
+            error_msg = 'radiosonde_auto_rx failed to start. Check SDR device connection.'
+            if stderr_output:
+                error_msg += f' Error: {stderr_output[:200]}'
+            return jsonify({'status': 'error', 'message': error_msg}), 500
+
+        radiosonde_running = True
+        radiosonde_active_device = device_int
+        radiosonde_active_sdr_type = sdr_type_str
+
+        # Clear stale data
+        with _balloons_lock:
+            radiosonde_balloons.clear()
+
+        # Start UDP listener thread
+        udp_thread = threading.Thread(
+            target=parse_radiosonde_udp,
+            args=(RADIOSONDE_UDP_PORT,),
+            daemon=True,
+        )
+        udp_thread.start()
+
+        return jsonify({
+            'status': 'started',
+            'message': 'Radiosonde tracking started',
+            'device': device,
+        })
+    except Exception as e:
+        app_module.release_sdr_device(device_int, sdr_type_str)
+        logger.error(f"Failed to start radiosonde_auto_rx: {e}")
+        return jsonify({'status': 'error', 'message': str(e)}), 500
+
+
+@radiosonde_bp.route('/stop', methods=['POST'])
+def stop_radiosonde():
+    """Stop radiosonde tracking."""
+    global radiosonde_running, radiosonde_active_device, radiosonde_active_sdr_type, _udp_socket
+
+    with app_module.radiosonde_lock:
+        if app_module.radiosonde_process:
+            try:
+                pgid = os.getpgid(app_module.radiosonde_process.pid)
+                os.killpg(pgid, 15)
+                app_module.radiosonde_process.wait(timeout=RADIOSONDE_TERMINATE_TIMEOUT)
+            except (subprocess.TimeoutExpired, ProcessLookupError, OSError):
+                try:
+                    pgid = os.getpgid(app_module.radiosonde_process.pid)
+                    os.killpg(pgid, 9)
+                except (ProcessLookupError, OSError):
+                    pass
+            app_module.radiosonde_process = None
+            logger.info("Radiosonde process stopped")
+
+        # Close UDP socket to unblock listener thread
+        if _udp_socket:
+            try:
+                _udp_socket.close()
+            except OSError:
+                pass
+            _udp_socket = None
+
+        # Release SDR device
+        if radiosonde_active_device is not None:
+            app_module.release_sdr_device(
+                radiosonde_active_device,
+                radiosonde_active_sdr_type or 'rtlsdr',
+            )
+
+        radiosonde_running = False
+        radiosonde_active_device = None
+        radiosonde_active_sdr_type = None
+
+    with _balloons_lock:
+        radiosonde_balloons.clear()
+
+    return jsonify({'status': 'stopped'})
+
+
+@radiosonde_bp.route('/stream')
+def stream_radiosonde():
+    """SSE stream for radiosonde telemetry."""
+    response = Response(
+        sse_stream_fanout(
+            source_queue=app_module.radiosonde_queue,
+            channel_key='radiosonde',
+            timeout=SSE_QUEUE_TIMEOUT,
+            keepalive_interval=SSE_KEEPALIVE_INTERVAL,
+        ),
+        mimetype='text/event-stream',
+    )
+    response.headers['Cache-Control'] = 'no-cache'
+    response.headers['X-Accel-Buffering'] = 'no'
+    return response
+
+
+@radiosonde_bp.route('/balloons')
+def get_balloons():
+    """Get current balloon data."""
+    with _balloons_lock:
+        return jsonify({
+            'status': 'success',
+            'count': len(radiosonde_balloons),
+            'balloons': dict(radiosonde_balloons),
+        })
diff --git a/setup.sh b/setup.sh
index 148fd6f..e60fd77 100755
--- a/setup.sh
+++ b/setup.sh
@@ -229,6 +229,7 @@ check_tools() {
   check_optional "dumpvdl2"    "VDL2 decoder" dumpvdl2
   check_required "AIS-catcher" "AIS vessel decoder" AIS-catcher aiscatcher
   check_optional "satdump" "Weather satellite decoder (NOAA/Meteor)" satdump
+  check_optional "auto_rx.py" "Radiosonde weather balloon decoder" auto_rx.py
   echo
   info "GPS:"
   check_required "gpsd" "GPS daemon" gpsd
@@ -816,6 +817,37 @@ WRAPPER
   )
 }
 
+install_radiosonde_auto_rx() {
+  info "Installing radiosonde_auto_rx (weather balloon decoder)..."
+  local install_dir="/opt/radiosonde_auto_rx"
+
+  (
+    tmp_dir="$(mktemp -d)"
+    trap 'rm -rf "$tmp_dir"' EXIT
+
+    info "Cloning radiosonde_auto_rx..."
+    if ! git clone --depth 1 https://github.com/projecthorus/radiosonde_auto_rx.git "$tmp_dir/radiosonde_auto_rx"; then
+      warn "Failed to clone radiosonde_auto_rx"
+      exit 1
+    fi
+
+    info "Installing Python dependencies..."
+    cd "$tmp_dir/radiosonde_auto_rx/auto_rx"
+    pip3 install --quiet -r requirements.txt || {
+      warn "Failed to install radiosonde_auto_rx Python dependencies"
+      exit 1
+    }
+
+    info "Installing to ${install_dir}..."
+    refresh_sudo
+    $SUDO mkdir -p "$install_dir/auto_rx"
+    $SUDO cp -r . "$install_dir/auto_rx/"
+    $SUDO chmod +x "$install_dir/auto_rx/auto_rx.py"
+
+    ok "radiosonde_auto_rx installed to ${install_dir}"
+  )
+}
+
 install_macos_packages() {
   need_sudo
 
@@ -825,7 +857,7 @@ install_macos_packages() {
     sudo -v || { fail "sudo authentication failed"; exit 1; }
   fi
 
-  TOTAL_STEPS=21
+  TOTAL_STEPS=22
   CURRENT_STEP=0
 
   progress "Checking Homebrew"
@@ -912,6 +944,19 @@ install_macos_packages() {
     ok "SatDump already installed"
   fi
 
+  progress "Installing radiosonde_auto_rx (optional)"
+  if ! cmd_exists auto_rx.py && [ ! -f /opt/radiosonde_auto_rx/auto_rx/auto_rx.py ]; then
+    echo
+    info "radiosonde_auto_rx is used for weather balloon (radiosonde) tracking."
+    if ask_yes_no "Do you want to install radiosonde_auto_rx?"; then
+      install_radiosonde_auto_rx || warn "radiosonde_auto_rx installation failed. Radiosonde tracking will not be available."
+    else
+      warn "Skipping radiosonde_auto_rx. You can install it later if needed."
+    fi
+  else
+    ok "radiosonde_auto_rx already installed"
+  fi
+
   progress "Installing aircrack-ng"
   brew_install aircrack-ng
 
@@ -1303,7 +1348,7 @@ install_debian_packages() {
     export NEEDRESTART_MODE=a
   fi
 
-  TOTAL_STEPS=27
+  TOTAL_STEPS=28
   CURRENT_STEP=0
 
   progress "Updating APT package lists"
@@ -1485,6 +1530,19 @@ install_debian_packages() {
     ok "SatDump already installed"
   fi
 
+  progress "Installing radiosonde_auto_rx (optional)"
+  if ! cmd_exists auto_rx.py && [ ! -f /opt/radiosonde_auto_rx/auto_rx/auto_rx.py ]; then
+    echo
+    info "radiosonde_auto_rx is used for weather balloon (radiosonde) tracking."
+    if ask_yes_no "Do you want to install radiosonde_auto_rx?"; then
+      install_radiosonde_auto_rx || warn "radiosonde_auto_rx installation failed. Radiosonde tracking will not be available."
+    else
+      warn "Skipping radiosonde_auto_rx. You can install it later if needed."
+    fi
+  else
+    ok "radiosonde_auto_rx already installed"
+  fi
+
   progress "Configuring udev rules"
   setup_udev_rules_debian
 
diff --git a/static/css/modes/radiosonde.css b/static/css/modes/radiosonde.css
new file mode 100644
index 0000000..9cb503a
--- /dev/null
+++ b/static/css/modes/radiosonde.css
@@ -0,0 +1,152 @@
+/* ============================================
+   RADIOSONDE MODE — Scoped Styles
+   ============================================ */
+
+/* Visuals container */
+.radiosonde-visuals-container {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+    flex: 1;
+    min-height: 0;
+    overflow: hidden;
+    padding: 8px;
+}
+
+/* Map container */
+#radiosondeMapContainer {
+    flex: 1;
+    min-height: 300px;
+    border-radius: 6px;
+    border: 1px solid var(--border-color);
+    background: var(--bg-primary);
+}
+
+/* Card container below map */
+.radiosonde-card-container {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 8px;
+    max-height: 200px;
+    overflow-y: auto;
+    padding: 4px 0;
+}
+
+/* Individual balloon card */
+.radiosonde-card {
+    background: var(--bg-card, #1a1e2e);
+    border: 1px solid var(--border-color);
+    border-radius: 6px;
+    padding: 10px 12px;
+    cursor: pointer;
+    flex: 1 1 280px;
+    min-width: 260px;
+    max-width: 400px;
+    transition: border-color 0.2s ease, background 0.2s ease;
+}
+
+.radiosonde-card:hover {
+    border-color: var(--accent-cyan);
+    background: rgba(0, 204, 255, 0.04);
+}
+
+.radiosonde-card-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 8px;
+    padding-bottom: 6px;
+    border-bottom: 1px solid var(--border-color);
+}
+
+.radiosonde-serial {
+    font-family: var(--font-mono, 'JetBrains Mono', monospace);
+    font-size: 13px;
+    font-weight: 600;
+    color: var(--accent-cyan);
+    letter-spacing: 0.5px;
+}
+
+.radiosonde-type {
+    font-family: var(--font-mono, 'JetBrains Mono', monospace);
+    font-size: 10px;
+    font-weight: 600;
+    color: var(--text-dim);
+    background: rgba(255, 255, 255, 0.06);
+    padding: 2px 6px;
+    border-radius: 3px;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+}
+
+/* Telemetry stat grid */
+.radiosonde-stats {
+    display: grid;
+    grid-template-columns: repeat(3, 1fr);
+    gap: 6px;
+}
+
+.radiosonde-stat {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    padding: 4px;
+}
+
+.radiosonde-stat-value {
+    font-family: var(--font-mono, 'JetBrains Mono', monospace);
+    font-size: 12px;
+    font-weight: 600;
+    color: var(--text-primary);
+    white-space: nowrap;
+}
+
+.radiosonde-stat-label {
+    font-size: 9px;
+    font-weight: 600;
+    color: var(--text-dim);
+    text-transform: uppercase;
+    letter-spacing: 0.8px;
+    margin-top: 2px;
+}
+
+/* Leaflet popup overrides for radiosonde */
+#radiosondeMapContainer .leaflet-popup-content-wrapper {
+    background: var(--bg-card, #1a1e2e);
+    color: var(--text-primary);
+    border: 1px solid var(--border-color);
+    border-radius: 6px;
+    font-family: var(--font-mono, 'JetBrains Mono', monospace);
+    font-size: 11px;
+}
+
+#radiosondeMapContainer .leaflet-popup-tip {
+    background: var(--bg-card, #1a1e2e);
+    border: 1px solid var(--border-color);
+}
+
+/* Scrollbar for card container */
+.radiosonde-card-container::-webkit-scrollbar {
+    width: 4px;
+}
+
+.radiosonde-card-container::-webkit-scrollbar-track {
+    background: transparent;
+}
+
+.radiosonde-card-container::-webkit-scrollbar-thumb {
+    background: var(--border-color);
+    border-radius: 2px;
+}
+
+/* Responsive: stack cards on narrow screens */
+@media (max-width: 600px) {
+    .radiosonde-card {
+        flex: 1 1 100%;
+        max-width: 100%;
+    }
+
+    .radiosonde-stats {
+        grid-template-columns: repeat(2, 1fr);
+    }
+}
diff --git a/templates/index.html b/templates/index.html
index 58d1497..2844a23 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -83,6 +83,7 @@
             spaceweather: "{{ url_for('static', filename='css/modes/space-weather.css') }}",
             wefax: "{{ url_for('static', filename='css/modes/wefax.css') }}",
             morse: "{{ url_for('static', filename='css/modes/morse.css') }}",
+            radiosonde: "{{ url_for('static', filename='css/modes/radiosonde.css') }}",
             system: "{{ url_for('static', filename='css/modes/system.css') }}"
         };
         window.INTERCEPT_MODE_STYLE_LOADED = {};
@@ -307,6 +308,10 @@
                                 <span class="mode-icon icon"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="10" r="3"/><path d="M12 21.7C17.3 17 20 13 20 10a8 8 0 1 0-16 0c0 3 2.7 7 8 11.7z"/></svg></span>
                                 <span class="mode-name">GPS</span>
                             </button>
+                            <button class="mode-card mode-card-sm" onclick="selectMode('radiosonde')">
+                                <span class="mode-icon icon"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 2v6"/><circle cx="12" cy="12" r="4"/><path d="M12 16v6"/><path d="M4.93 4.93l4.24 4.24"/><path d="M14.83 14.83l4.24 4.24"/></svg></span>
+                                <span class="mode-name">Radiosonde</span>
+                            </button>
                         </div>
                     </div>
 
@@ -696,6 +701,8 @@
 
                 {% include 'partials/modes/ais.html' %}
 
+                {% include 'partials/modes/radiosonde.html' %}
+
                 {% include 'partials/modes/spy-stations.html' %}
 
                 {% include 'partials/modes/meshtastic.html' %}
@@ -3127,6 +3134,12 @@
                     </div>
                 </div>
 
+                <!-- Radiosonde Visuals -->
+                <div id="radiosondeVisuals" class="radiosonde-visuals-container" style="display: none;">
+                    <div id="radiosondeMapContainer" style="flex: 1; min-height: 300px; border-radius: 6px; border: 1px solid var(--border-color); background: var(--bg-primary);"></div>
+                    <div id="radiosondeCardContainer" class="radiosonde-card-container"></div>
+                </div>
+
                 <!-- System Health Visuals -->
                 <div id="systemVisuals" class="sys-visuals-container" style="display: none;">
                     <div class="sys-dashboard">
@@ -3387,6 +3400,7 @@
             subghz: { label: 'SubGHz', indicator: 'SUBGHZ', outputTitle: 'SubGHz Transceiver', group: 'signals' },
             aprs: { label: 'APRS', indicator: 'APRS', outputTitle: 'APRS Tracker', group: 'tracking' },
             gps: { label: 'GPS', indicator: 'GPS', outputTitle: 'GPS Receiver', group: 'tracking' },
+            radiosonde: { label: 'Radiosonde', indicator: 'SONDE', outputTitle: 'Radiosonde Decoder', group: 'tracking' },
             satellite: { label: 'Satellite', indicator: 'SATELLITE', outputTitle: 'Satellite Monitor', group: 'space' },
             sstv: { label: 'ISS SSTV', indicator: 'ISS SSTV', outputTitle: 'ISS SSTV Decoder', group: 'space' },
             weathersat: { label: 'Weather Sat', indicator: 'WEATHER SAT', outputTitle: 'Weather Satellite Decoder', group: 'space' },
@@ -4175,6 +4189,7 @@
             document.getElementById('aprsMode')?.classList.toggle('active', mode === 'aprs');
             document.getElementById('tscmMode')?.classList.toggle('active', mode === 'tscm');
             document.getElementById('aisMode')?.classList.toggle('active', mode === 'ais');
+            document.getElementById('radiosondeMode')?.classList.toggle('active', mode === 'radiosonde');
             document.getElementById('spystationsMode')?.classList.toggle('active', mode === 'spystations');
             document.getElementById('meshtasticMode')?.classList.toggle('active', mode === 'meshtastic');
             document.getElementById('websdrMode')?.classList.toggle('active', mode === 'websdr');
@@ -4224,6 +4239,7 @@
             const wefaxVisuals = document.getElementById('wefaxVisuals');
             const spaceWeatherVisuals = document.getElementById('spaceWeatherVisuals');
             const waterfallVisuals = document.getElementById('waterfallVisuals');
+            const radiosondeVisuals = document.getElementById('radiosondeVisuals');
             const systemVisuals = document.getElementById('systemVisuals');
             if (wifiLayoutContainer) wifiLayoutContainer.style.display = mode === 'wifi' ? 'flex' : 'none';
             if (btLayoutContainer) btLayoutContainer.style.display = mode === 'bluetooth' ? 'flex' : 'none';
@@ -4242,6 +4258,7 @@
             if (wefaxVisuals) wefaxVisuals.style.display = mode === 'wefax' ? 'flex' : 'none';
             if (spaceWeatherVisuals) spaceWeatherVisuals.style.display = mode === 'spaceweather' ? 'flex' : 'none';
             if (waterfallVisuals) waterfallVisuals.style.display = mode === 'waterfall' ? 'flex' : 'none';
+            if (radiosondeVisuals) radiosondeVisuals.style.display = mode === 'radiosonde' ? 'flex' : 'none';
             if (systemVisuals) systemVisuals.style.display = mode === 'system' ? 'flex' : 'none';
 
             // Prevent Leaflet heatmap redraws on hidden BT Locate map containers.
@@ -4329,7 +4346,7 @@
             // Show RTL-SDR device section for modes that use it
             const rtlDeviceSection = document.getElementById('rtlDeviceSection');
             if (rtlDeviceSection) {
-                rtlDeviceSection.style.display = (mode === 'pager' || mode === 'sensor' || mode === 'rtlamr' || mode === 'aprs' || mode === 'sstv' || mode === 'weathersat' || mode === 'sstv_general' || mode === 'wefax' || mode === 'morse') ? 'block' : 'none';
+                rtlDeviceSection.style.display = (mode === 'pager' || mode === 'sensor' || mode === 'rtlamr' || mode === 'aprs' || mode === 'sstv' || mode === 'weathersat' || mode === 'sstv_general' || mode === 'wefax' || mode === 'morse' || mode === 'radiosonde') ? 'block' : 'none';
                 // Save original sidebar position of SDR device section (once)
                 if (!rtlDeviceSection._origParent) {
                     rtlDeviceSection._origParent = rtlDeviceSection.parentNode;
@@ -4434,6 +4451,11 @@
                 if (typeof Waterfall !== 'undefined') Waterfall.init();
             } else if (mode === 'morse') {
                 MorseMode.init();
+            } else if (mode === 'radiosonde') {
+                initRadiosondeMap();
+                setTimeout(() => {
+                    if (radiosondeMap) radiosondeMap.invalidateSize();
+                }, 100);
             } else if (mode === 'system') {
                 SystemHealth.init();
             }
diff --git a/templates/partials/modes/radiosonde.html b/templates/partials/modes/radiosonde.html
new file mode 100644
index 0000000..2b3a9dc
--- /dev/null
+++ b/templates/partials/modes/radiosonde.html
@@ -0,0 +1,376 @@
+<!-- RADIOSONDE WEATHER BALLOON TRACKING MODE -->
+<div id="radiosondeMode" class="mode-content">
+    <div class="section">
+        <h3>Radiosonde Decoder</h3>
+        <div class="info-text" style="margin-bottom: 15px;">
+            Track weather balloons via radiosonde telemetry on 400&ndash;406 MHz. Decodes position, altitude, temperature, humidity, and pressure.
+        </div>
+    </div>
+
+    <div class="section">
+        <h3>Settings</h3>
+        <div class="form-group">
+            <label>Region / Frequency Band</label>
+            <select id="radiosondeRegionSelect" onchange="updateRadiosondeFreqRange()">
+                <option value="global" selected>Global (400&ndash;406 MHz)</option>
+                <option value="eu">Europe (400&ndash;403 MHz)</option>
+                <option value="us">US (400&ndash;406 MHz)</option>
+                <option value="au">Australia (400&ndash;403 MHz)</option>
+                <option value="custom">Custom&hellip;</option>
+            </select>
+        </div>
+        <div class="form-group" id="radiosondeCustomFreqGroup" style="display: none;">
+            <label>Frequency Range (MHz)</label>
+            <div style="display: flex; gap: 8px; align-items: center;">
+                <input type="number" id="radiosondeFreqMin" value="400.0" min="380" max="410" step="0.1" style="width: 50%;" placeholder="Min">
+                <span style="color: var(--text-dim);">&ndash;</span>
+                <input type="number" id="radiosondeFreqMax" value="406.0" min="380" max="410" step="0.1" style="width: 50%;" placeholder="Max">
+            </div>
+        </div>
+        <div class="form-group">
+            <label>Gain (dB, 0 = auto)</label>
+            <input type="number" id="radiosondeGainInput" value="40" min="0" max="50" placeholder="0-50">
+        </div>
+    </div>
+
+    <div class="section">
+        <h3>Status</h3>
+        <div id="radiosondeStatusDisplay" class="info-text">
+            <p>Status: <span id="radiosondeStatusText" style="color: var(--accent-yellow);">Standby</span></p>
+            <p>Balloons: <span id="radiosondeBalloonCount">0</span></p>
+            <p>Last update: <span id="radiosondeLastUpdate">&mdash;</span></p>
+        </div>
+    </div>
+
+    <!-- Antenna Guide -->
+    <div class="section">
+        <h3>Antenna Guide</h3>
+        <div style="font-size: 11px; color: var(--text-dim); line-height: 1.5;">
+            <p style="margin-bottom: 8px; color: var(--accent-cyan); font-weight: 600;">
+                400 MHz meteorological band &mdash; stock SDR antenna may work for nearby launches
+            </p>
+
+            <div style="background: var(--bg-primary); border: 1px solid var(--border-color); border-radius: 4px; padding: 10px; margin-bottom: 10px;">
+                <strong style="color: var(--accent-cyan); font-size: 12px;">Simple Quarter-Wave</strong>
+                <ul style="margin: 6px 0 0 14px; padding: 0;">
+                    <li><strong style="color: var(--text-primary);">Element length:</strong> ~18.7 cm (quarter-wave at 400 MHz)</li>
+                    <li><strong style="color: var(--text-primary);">Material:</strong> Wire or copper rod</li>
+                    <li><strong style="color: var(--text-primary);">Orientation:</strong> Vertical</li>
+                    <li><strong style="color: var(--text-primary);">Placement:</strong> Outdoors, as high as possible with clear sky view</li>
+                </ul>
+            </div>
+
+            <div style="background: var(--bg-primary); border: 1px solid var(--border-color); border-radius: 4px; padding: 10px; margin-bottom: 10px;">
+                <strong style="color: var(--accent-cyan); font-size: 12px;">Tips</strong>
+                <ul style="margin: 6px 0 0 14px; padding: 0;">
+                    <li><strong style="color: var(--text-primary);">Range:</strong> 200+ km with LNA and good antenna placement</li>
+                    <li><strong style="color: var(--text-primary);">LNA:</strong> Recommended &mdash; mount near antenna for best results</li>
+                    <li><strong style="color: var(--text-primary);">Launches:</strong> Typically 2&times;/day at 00Z and 12Z from weather stations</li>
+                </ul>
+            </div>
+
+            <div style="background: var(--bg-primary); border: 1px solid var(--border-color); border-radius: 4px; padding: 10px;">
+                <strong style="color: var(--accent-cyan); font-size: 12px;">Quick Reference</strong>
+                <table style="width: 100%; margin-top: 6px; font-size: 10px; border-collapse: collapse;">
+                    <tr style="border-bottom: 1px solid var(--border-color);">
+                        <td style="padding: 3px 4px; color: var(--text-dim);">Frequency band</td>
+                        <td style="padding: 3px 4px; color: var(--text-primary); text-align: right;">400&ndash;406 MHz</td>
+                    </tr>
+                    <tr style="border-bottom: 1px solid var(--border-color);">
+                        <td style="padding: 3px 4px; color: var(--text-dim);">Quarter-wave length</td>
+                        <td style="padding: 3px 4px; color: var(--text-primary); text-align: right;">18.7 cm</td>
+                    </tr>
+                    <tr style="border-bottom: 1px solid var(--border-color);">
+                        <td style="padding: 3px 4px; color: var(--text-dim);">Common types</td>
+                        <td style="padding: 3px 4px; color: var(--text-primary); text-align: right;">RS41, RS92, DFM, M10</td>
+                    </tr>
+                    <tr style="border-bottom: 1px solid var(--border-color);">
+                        <td style="padding: 3px 4px; color: var(--text-dim);">Max altitude</td>
+                        <td style="padding: 3px 4px; color: var(--text-primary); text-align: right;">~35 km (115,000 ft)</td>
+                    </tr>
+                    <tr>
+                        <td style="padding: 3px 4px; color: var(--text-dim);">Flight duration</td>
+                        <td style="padding: 3px 4px; color: var(--text-primary); text-align: right;">~90 min ascent</td>
+                    </tr>
+                </table>
+            </div>
+        </div>
+    </div>
+
+    <button class="run-btn" id="startRadiosondeBtn" onclick="startRadiosondeTracking()">
+        Start Radiosonde Tracking
+    </button>
+    <button class="stop-btn" id="stopRadiosondeBtn" onclick="stopRadiosondeTracking()" style="display: none;">
+        Stop Radiosonde Tracking
+    </button>
+</div>
+
+<script>
+    let radiosondeEventSource = null;
+    let radiosondeBalloons = {};
+
+    function updateRadiosondeFreqRange() {
+        const region = document.getElementById('radiosondeRegionSelect').value;
+        const customGroup = document.getElementById('radiosondeCustomFreqGroup');
+        const minInput = document.getElementById('radiosondeFreqMin');
+        const maxInput = document.getElementById('radiosondeFreqMax');
+
+        const presets = {
+            global: [400.0, 406.0],
+            eu: [400.0, 403.0],
+            us: [400.0, 406.0],
+            au: [400.0, 403.0],
+        };
+
+        if (region === 'custom') {
+            customGroup.style.display = 'block';
+        } else {
+            customGroup.style.display = 'none';
+            if (presets[region]) {
+                minInput.value = presets[region][0];
+                maxInput.value = presets[region][1];
+            }
+        }
+    }
+
+    function startRadiosondeTracking() {
+        const gain = document.getElementById('radiosondeGainInput').value || '40';
+        const device = document.getElementById('deviceSelect')?.value || '0';
+        const freqMin = parseFloat(document.getElementById('radiosondeFreqMin').value) || 400.0;
+        const freqMax = parseFloat(document.getElementById('radiosondeFreqMax').value) || 406.0;
+
+        fetch('/radiosonde/start', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                device,
+                gain,
+                freq_min: freqMin,
+                freq_max: freqMax,
+                bias_t: typeof getBiasTEnabled === 'function' ? getBiasTEnabled() : false,
+            })
+        })
+        .then(r => r.json())
+        .then(data => {
+            if (data.status === 'started' || data.status === 'already_running') {
+                document.getElementById('startRadiosondeBtn').style.display = 'none';
+                document.getElementById('stopRadiosondeBtn').style.display = 'block';
+                document.getElementById('radiosondeStatusText').textContent = 'Tracking';
+                document.getElementById('radiosondeStatusText').style.color = 'var(--accent-green)';
+                startRadiosondeSSE();
+            } else {
+                alert(data.message || 'Failed to start radiosonde tracking');
+            }
+        })
+        .catch(err => alert('Error: ' + err.message));
+    }
+
+    function stopRadiosondeTracking() {
+        fetch('/radiosonde/stop', { method: 'POST' })
+        .then(r => r.json())
+        .then(() => {
+            document.getElementById('startRadiosondeBtn').style.display = 'block';
+            document.getElementById('stopRadiosondeBtn').style.display = 'none';
+            document.getElementById('radiosondeStatusText').textContent = 'Standby';
+            document.getElementById('radiosondeStatusText').style.color = 'var(--accent-yellow)';
+            document.getElementById('radiosondeBalloonCount').textContent = '0';
+            document.getElementById('radiosondeLastUpdate').textContent = '\u2014';
+            if (radiosondeEventSource) {
+                radiosondeEventSource.close();
+                radiosondeEventSource = null;
+            }
+            radiosondeBalloons = {};
+            // Clear map markers
+            if (typeof radiosondeMap !== 'undefined' && radiosondeMap) {
+                radiosondeMarkers.forEach(m => radiosondeMap.removeLayer(m));
+                radiosondeMarkers.clear();
+                radiosondeTracks.forEach(t => radiosondeMap.removeLayer(t));
+                radiosondeTracks.clear();
+            }
+        });
+    }
+
+    function startRadiosondeSSE() {
+        if (radiosondeEventSource) radiosondeEventSource.close();
+
+        radiosondeEventSource = new EventSource('/radiosonde/stream');
+        radiosondeEventSource.onmessage = function(e) {
+            try {
+                const data = JSON.parse(e.data);
+                if (data.type === 'balloon') {
+                    radiosondeBalloons[data.id] = data;
+                    document.getElementById('radiosondeBalloonCount').textContent = Object.keys(radiosondeBalloons).length;
+                    const now = new Date();
+                    document.getElementById('radiosondeLastUpdate').textContent =
+                        now.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit', second: '2-digit' });
+                    updateRadiosondeMap(data);
+                    updateRadiosondeCards();
+                }
+            } catch (err) {}
+        };
+
+        radiosondeEventSource.onerror = function() {
+            setTimeout(() => {
+                if (document.getElementById('stopRadiosondeBtn').style.display === 'block') {
+                    startRadiosondeSSE();
+                }
+            }, 2000);
+        };
+    }
+
+    // Map management
+    let radiosondeMap = null;
+    let radiosondeMarkers = new Map();
+    let radiosondeTracks = new Map();
+    let radiosondeTrackPoints = new Map();
+
+    function initRadiosondeMap() {
+        if (radiosondeMap) return;
+        const container = document.getElementById('radiosondeMapContainer');
+        if (!container) return;
+
+        radiosondeMap = L.map('radiosondeMapContainer', {
+            center: [40, -95],
+            zoom: 4,
+            zoomControl: true,
+        });
+
+        L.tileLayer('https://{s}.basemaps.cartocdn.com/dark_all/{z}/{x}/{y}{r}.png', {
+            attribution: '&copy; OpenStreetMap &copy; CARTO',
+            maxZoom: 18,
+        }).addTo(radiosondeMap);
+    }
+
+    function updateRadiosondeMap(balloon) {
+        if (!radiosondeMap || !balloon.lat || !balloon.lon) return;
+
+        const id = balloon.id;
+        const latlng = [balloon.lat, balloon.lon];
+
+        // Altitude-based colour coding
+        const alt = balloon.alt || 0;
+        let colour;
+        if (alt < 5000) colour = '#00ff88';
+        else if (alt < 15000) colour = '#00ccff';
+        else if (alt < 25000) colour = '#ff9900';
+        else colour = '#ff3366';
+
+        // Update or create marker
+        if (radiosondeMarkers.has(id)) {
+            radiosondeMarkers.get(id).setLatLng(latlng);
+        } else {
+            const marker = L.circleMarker(latlng, {
+                radius: 7,
+                color: colour,
+                fillColor: colour,
+                fillOpacity: 0.8,
+                weight: 2,
+            }).addTo(radiosondeMap);
+            radiosondeMarkers.set(id, marker);
+        }
+
+        // Update marker colour based on altitude
+        radiosondeMarkers.get(id).setStyle({ color: colour, fillColor: colour });
+
+        // Build popup content
+        const altStr = alt ? `${Math.round(alt).toLocaleString()} m` : '--';
+        const tempStr = balloon.temp != null ? `${balloon.temp.toFixed(1)} °C` : '--';
+        const humStr = balloon.humidity != null ? `${balloon.humidity.toFixed(0)}%` : '--';
+        const velStr = balloon.vel_v != null ? `${balloon.vel_v.toFixed(1)} m/s` : '--';
+        radiosondeMarkers.get(id).bindPopup(
+            `<strong>${id}</strong><br>` +
+            `Type: ${balloon.sonde_type || '--'}<br>` +
+            `Alt: ${altStr}<br>` +
+            `Temp: ${tempStr} | Hum: ${humStr}<br>` +
+            `Vert: ${velStr}<br>` +
+            (balloon.freq ? `Freq: ${balloon.freq.toFixed(3)} MHz` : '')
+        );
+
+        // Track polyline
+        if (!radiosondeTrackPoints.has(id)) {
+            radiosondeTrackPoints.set(id, []);
+        }
+        radiosondeTrackPoints.get(id).push(latlng);
+
+        if (radiosondeTracks.has(id)) {
+            radiosondeTracks.get(id).setLatLngs(radiosondeTrackPoints.get(id));
+        } else {
+            const track = L.polyline(radiosondeTrackPoints.get(id), {
+                color: colour,
+                weight: 2,
+                opacity: 0.6,
+                dashArray: '4 4',
+            }).addTo(radiosondeMap);
+            radiosondeTracks.set(id, track);
+        }
+
+        // Auto-centre on first balloon
+        if (radiosondeMarkers.size === 1) {
+            radiosondeMap.setView(latlng, 8);
+        }
+    }
+
+    function updateRadiosondeCards() {
+        const container = document.getElementById('radiosondeCardContainer');
+        if (!container) return;
+
+        const sorted = Object.values(radiosondeBalloons).sort((a, b) => (b.alt || 0) - (a.alt || 0));
+        container.innerHTML = sorted.map(b => {
+            const alt = b.alt ? `${Math.round(b.alt).toLocaleString()} m` : '--';
+            const temp = b.temp != null ? `${b.temp.toFixed(1)}°C` : '--';
+            const hum = b.humidity != null ? `${b.humidity.toFixed(0)}%` : '--';
+            const press = b.pressure != null ? `${b.pressure.toFixed(1)} hPa` : '--';
+            const vel = b.vel_v != null ? `${b.vel_v > 0 ? '+' : ''}${b.vel_v.toFixed(1)} m/s` : '--';
+            const freq = b.freq ? `${b.freq.toFixed(3)} MHz` : '--';
+            return `
+                <div class="radiosonde-card" onclick="radiosondeMap && radiosondeMap.setView([${b.lat || 0}, ${b.lon || 0}], 10)">
+                    <div class="radiosonde-card-header">
+                        <span class="radiosonde-serial">${b.id}</span>
+                        <span class="radiosonde-type">${b.sonde_type || '??'}</span>
+                    </div>
+                    <div class="radiosonde-stats">
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${alt}</span>
+                            <span class="radiosonde-stat-label">ALT</span>
+                        </div>
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${temp}</span>
+                            <span class="radiosonde-stat-label">TEMP</span>
+                        </div>
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${hum}</span>
+                            <span class="radiosonde-stat-label">HUM</span>
+                        </div>
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${press}</span>
+                            <span class="radiosonde-stat-label">PRESS</span>
+                        </div>
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${vel}</span>
+                            <span class="radiosonde-stat-label">VERT</span>
+                        </div>
+                        <div class="radiosonde-stat">
+                            <span class="radiosonde-stat-value">${freq}</span>
+                            <span class="radiosonde-stat-label">FREQ</span>
+                        </div>
+                    </div>
+                </div>
+            `;
+        }).join('');
+    }
+
+    // Check initial status on load
+    fetch('/radiosonde/status')
+    .then(r => r.json())
+    .then(data => {
+        if (data.tracking_active) {
+            document.getElementById('startRadiosondeBtn').style.display = 'none';
+            document.getElementById('stopRadiosondeBtn').style.display = 'block';
+            document.getElementById('radiosondeStatusText').textContent = 'Tracking';
+            document.getElementById('radiosondeStatusText').style.color = 'var(--accent-green)';
+            document.getElementById('radiosondeBalloonCount').textContent = data.balloon_count || 0;
+            startRadiosondeSSE();
+        }
+    })
+    .catch(() => {});
+</script>
diff --git a/templates/partials/nav.html b/templates/partials/nav.html
index 68a6d6c..dfee292 100644
--- a/templates/partials/nav.html
+++ b/templates/partials/nav.html
@@ -84,6 +84,7 @@
             {{ mode_item('ais', 'Vessels', '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M3 18l2 2h14l2-2"/><path d="M5 18v-4a2 2 0 0 1 2-2h10a2 2 0 0 1 2 2v4"/><path d="M12 12V6"/><path d="M12 6l4 3"/></svg>', '/ais/dashboard') }}
             {{ mode_item('aprs', 'APRS', '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M20 10c0 6-8 12-8 12s-8-6-8-12a8 8 0 0 1 16 0Z"/><circle cx="12" cy="10" r="3"/></svg>') }}
             {{ mode_item('gps', 'GPS', '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="10" r="3"/><path d="M12 21.7C17.3 17 20 13 20 10a8 8 0 1 0-16 0c0 3 2.7 7 8 11.7z"/></svg>') }}
+            {{ mode_item('radiosonde', 'Radiosonde', '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 2v6"/><circle cx="12" cy="12" r="4"/><path d="M12 16v6"/><path d="M4.93 4.93l4.24 4.24"/><path d="M14.83 14.83l4.24 4.24"/></svg>') }}
         </div>
     </div>
 
diff --git a/utils/constants.py b/utils/constants.py
index a0be48b..85552bd 100644
--- a/utils/constants.py
+++ b/utils/constants.py
@@ -300,6 +300,20 @@ SUBGHZ_PRESETS = {
 }
 
 
+# =============================================================================
+# RADIOSONDE (Weather Balloon Tracking)
+# =============================================================================
+
+# UDP port for radiosonde_auto_rx telemetry broadcast
+RADIOSONDE_UDP_PORT = 55673
+
+# Radiosonde process termination timeout
+RADIOSONDE_TERMINATE_TIMEOUT = 5
+
+# Maximum age for balloon data before cleanup (30 min — balloons move slowly)
+MAX_RADIOSONDE_AGE_SECONDS = 1800
+
+
 # =============================================================================
 # DEAUTH ATTACK DETECTION
 # =============================================================================
diff --git a/utils/dependencies.py b/utils/dependencies.py
index 933be4b..72c2bf2 100644
--- a/utils/dependencies.py
+++ b/utils/dependencies.py
@@ -1,11 +1,11 @@
 from __future__ import annotations
 
-import logging
-import os
-import platform
-import shutil
-import subprocess
-from typing import Any
+import logging
+import os
+import platform
+import shutil
+import subprocess
+from typing import Any
 
 logger = logging.getLogger('intercept.dependencies')
 
@@ -18,32 +18,32 @@ def check_tool(name: str) -> bool:
     return get_tool_path(name) is not None
 
 
-def get_tool_path(name: str) -> str | None:
-    """Get the full path to a tool, checking standard PATH and extra locations."""
-    # Optional explicit override, e.g. INTERCEPT_RTL_FM_PATH=/opt/homebrew/bin/rtl_fm
-    env_key = f"INTERCEPT_{name.upper().replace('-', '_')}_PATH"
-    env_path = os.environ.get(env_key)
-    if env_path and os.path.isfile(env_path) and os.access(env_path, os.X_OK):
-        return env_path
-
-    # Prefer native Homebrew binaries on Apple Silicon to avoid mixing Rosetta
-    # /usr/local tools with arm64 Python/runtime.
-    if platform.system() == 'Darwin':
-        machine = platform.machine().lower()
-        preferred_paths: list[str] = []
-        if machine in {'arm64', 'aarch64'}:
-            preferred_paths.append('/opt/homebrew/bin')
-        preferred_paths.append('/usr/local/bin')
-
-        for base in preferred_paths:
-            full_path = os.path.join(base, name)
-            if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
-                return full_path
-
-    # First check standard PATH
-    path = shutil.which(name)
-    if path:
-        return path
+def get_tool_path(name: str) -> str | None:
+    """Get the full path to a tool, checking standard PATH and extra locations."""
+    # Optional explicit override, e.g. INTERCEPT_RTL_FM_PATH=/opt/homebrew/bin/rtl_fm
+    env_key = f"INTERCEPT_{name.upper().replace('-', '_')}_PATH"
+    env_path = os.environ.get(env_key)
+    if env_path and os.path.isfile(env_path) and os.access(env_path, os.X_OK):
+        return env_path
+
+    # Prefer native Homebrew binaries on Apple Silicon to avoid mixing Rosetta
+    # /usr/local tools with arm64 Python/runtime.
+    if platform.system() == 'Darwin':
+        machine = platform.machine().lower()
+        preferred_paths: list[str] = []
+        if machine in {'arm64', 'aarch64'}:
+            preferred_paths.append('/opt/homebrew/bin')
+        preferred_paths.append('/usr/local/bin')
+
+        for base in preferred_paths:
+            full_path = os.path.join(base, name)
+            if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
+                return full_path
+
+    # First check standard PATH
+    path = shutil.which(name)
+    if path:
+        return path
 
     # Check additional paths (e.g., /usr/sbin for aircrack-ng on Debian)
     for extra_path in EXTRA_TOOL_PATHS:
@@ -447,6 +447,20 @@ TOOL_DEPENDENCIES = {
             }
         }
     },
+    'radiosonde': {
+        'name': 'Radiosonde Tracking',
+        'tools': {
+            'auto_rx.py': {
+                'required': True,
+                'description': 'Radiosonde weather balloon decoder',
+                'install': {
+                    'apt': 'Run ./setup.sh (clones from GitHub)',
+                    'brew': 'Run ./setup.sh (clones from GitHub)',
+                    'manual': 'https://github.com/projecthorus/radiosonde_auto_rx'
+                }
+            }
+        }
+    },
     'tscm': {
         'name': 'TSCM Counter-Surveillance',
         'tools': {