ECMWF Weather Forecast API

This API provides access to both real-time IFS HRES 9 km forecasts and open-data ECMWF IFS and AIFS 0.25°. Different weather models may use different temporal resolutions. The Open-Meteo API dynamically interpolates all data to a consistent 1-hourly time-series for up to 15 days.

• The ECMWF IFS model runs every 6 hours at a 9 km resolution. Open-Meteo delivers the full native 9 km IFS forecasts on the reduced Gaussian grid O1280, ensuring direct, original ECMWF outputs at the highest resolution. The first 90 forecast hours use 1-hourly data, switching to 3-hourly after 90 hours and 6 hourly after 144 hours.
• The open-data IFS 0.25 updates every 6 hours, but only offers 0.25° resolution and 3- and 6-hourly data. The open-data distribution has an additional delay of 2 hours compared to the real-time IFS dissemination.
• AIFS is ECMWF’s artificial intelligence weather model, delivering improved performance compared to GraphCast and other AI-based models. Currently, only 6-hourly time steps are available. More details about AIFS can be found here. As ECMWF expands its data offering, new AIFS products will also be integrated into this API.

For higher-resolution local forecasts, we recommend the Generic Weather Forecast API, which integrates models down to 1 km resolution. ECMWF ensemble forecasts are available via the Ensemble API, ECMWF WAM wave forecasts can be accessed through the Marine Forecast API, and HRES IFS data are archived in the Historical Weather API.

The API endpoint /v1/ecmwf accepts a geographical coordinate, a list of weather variables and responds with a JSON hourly weather forecast for 10 days. Time always starts at 0:00 today. All URL parameters are listed below:

The parameter &hourly= accepts the following values. Most weather variables are given as an instantaneous value for the indicated hour. Some variables like precipitation are calculated from the preceding hour as and average or sum.

On success a JSON object will be returned.

{
    "latitude": 52.52,
    "longitude": 13.419,
    "elevation": 44.812,
    "generationtime_ms": 2.2119,
    "utc_offset_seconds": 0,
    "timezone": "Europe/Berlin",
    "timezone_abbreviation": "CEST",
    "hourly": {
        "time": ["2022-07-01T00:00", "2022-07-01T01:00", "2022-07-01T02:00", ...],
        "temperature_2m": [13, 12.7, 12.7, 12.5, 12.5, 12.8, 13, 12.9, 13.3, ...]
    },
    "hourly_units": {
        "temperature_2m": "°C"
    }
}

In case an error occurs, for example a URL parameter is not correctly specified, a JSON error object is returned with a HTTP 400 status code.

{
    "error": true, 
    "reason": "Cannot initialize WeatherVariable from invalid String value
	    tempeture_2m for key hourly" 
}

WMO Weather interpretation codes (WW)

(*) Thunderstorm forecast with hail is only available in Central Europe