JMA Data MCP

Instructions

Implementation Reference

• jma_data_mcp/server.py:219-265 (handler)

  The MCP tool handler for get_historical_weather. Parses the target_datetime, fetches historical data using fetch_historical_amedas_data, adds station information, and returns the result. Also serves as registration via @mcp.tool() decorator.
  @mcp.tool() async def get_historical_weather( station_code: str, target_datetime: str, ) -> dict: """Get historical weather data for a specific date and time. Data is available for approximately the past 1-2 weeks. Args: station_code: Station code (e.g., '44132' for Tokyo) target_datetime: Target datetime in ISO format (e.g., '2025-12-01T12:00:00') or 'YYYY-MM-DD HH:MM' format. Time is in JST. Returns: Weather data for the specified time """ try: if "T" in target_datetime: target_time = datetime.fromisoformat(target_datetime.replace("Z", "+00:00")) else: for fmt in ["%Y-%m-%d %H:%M", "%Y-%m-%d %H:%M:%S", "%Y/%m/%d %H:%M"]: try: target_time = datetime.strptime(target_datetime, fmt) break except ValueError: continue else: raise ValueError(f"Could not parse datetime: {target_datetime}") if target_time.tzinfo is None: target_time = target_time.replace(tzinfo=JST) except Exception as e: return { "error": f"Invalid datetime format: {e}", "hint": "Use ISO format (e.g., '2025-12-01T12:00:00') or 'YYYY-MM-DD HH:MM'", } historical_data = await fetch_historical_amedas_data(station_code, target_time) station_info = get_station(station_code) if station_info: historical_data["station_info"] = station_info return historical_data
• jma_data_mcp/weather.py:220-264 (helper)

  Helper function that performs the core logic: rounds time to 10-min interval, fetches JSON data from JMA AMeDAS API, parses the station data using _parse_station_data, and formats the response.
  async def fetch_historical_amedas_data( station_code: str, target_time: datetime ) -> dict[str, Any]: """ Fetch historical AMeDAS data for a specific time. Args: station_code: Station code (e.g., '44132' for Tokyo) target_time: Target datetime (available for approximately past 1-2 weeks) Returns: Dictionary with observation data for the specified time """ # Round to 10-minute intervals target_time = target_time.replace( minute=(target_time.minute // 10) * 10, second=0, microsecond=0 ) time_str = format_time_for_api(target_time) url = f'https://www.jma.go.jp/bosai/amedas/data/map/{time_str}.json' async with httpx.AsyncClient() as client: response = await client.get(url, timeout=30.0) response.raise_for_status() raw_data = response.json() station_data = raw_data.get(station_code) if station_data is None: return { "error": f"No data found for station {station_code} at {target_time.isoformat()}", "observation_time": target_time.isoformat() } result = { "observation_time": target_time.isoformat(), "observation_time_jst": target_time.strftime('%Y-%m-%d %H:%M JST'), "station_code": station_code, "data": _parse_station_data(station_code, station_data) } return result