Google WeatherNext 2 API
Weather forecasts from the Google WeatherNext 2 AI model
API Response
Note: This API call is equivalent to 6.4 calls because of factors like long time intervals, the number of locations, variables, or models involved.
Data Sources
Google DeepMind WeatherNext 2 is a global AI ensemble weather model with 64 members on a regular 0.25° latitude-longitude grid. The ensemble describes a range of possible weather developments and can be used to estimate forecast uncertainty and the risk of less likely events.
The source dataset contains 60 forecast steps at 6-hour intervals. It does not include forecast hour zero: the first value is valid 6 hours after model initialization and the last value is valid at 360 hours, or 15 days. Google produces runs initialized at 00, 06, 12 and 18 UTC. At present, Open-Meteo processes the 00 and 12 UTC runs because the 06 and 18 UTC data do not arrive in time for the current update schedule. See Google's dissemination schedule for upstream release times.
| Weather Model | Region | Spatial Resolution | Temporal Resolution | Forecast Length | Update frequency |
|---|---|---|---|---|---|
| Google WeatherNext 2 | 🌍 | 0.25° | 6-hourly | 15 days | Every 12 hours |
Native Model Variables
WeatherNext directly predicts the atmospheric fields listed below. Open-Meteo retains these fields or uses them to calculate more convenient API variables. In particular, the source model provides specific humidity and wind components rather than relative humidity, wind speed or wind direction.
| Native WeatherNext field | Level | Use in the Open-Meteo API |
|---|---|---|
| 2 m temperature | 2 m above ground | temperature_2m |
| Sea-surface temperature | Surface | sea_surface_temperature |
| Mean sea-level pressure | Mean sea level | pressure_msl and derived surface pressure |
| Total precipitation | Surface | precipitation, accumulated over the preceding 6 hours |
| U and V wind components | 10 m and 100 m above ground | Wind speed and direction at 10 and 100 m height above ground |
| Temperature | 13 pressure levels | Temperature and humidity-related pressure-level variables |
| Specific humidity | 13 pressure levels | Input for derived relative humidity |
| Geopotential | 13 pressure levels | Geopotential height |
| U and V wind components | 13 pressure levels | Pressure-level wind speed and direction |
| Vertical velocity | 13 pressure levels | Geometric vertical velocity |
The pressure levels are 1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100 and 50 hPa. See Google's model specification and data schema for the original dataset layout.
Derived Variables
Several convenient API variables are not predicted directly by WeatherNext. Open-Meteo derives them from the native fields for every ensemble member and forecast step.
| Derived Variable | How it is derived? |
|---|---|
| Relative humidity | Calculated at every pressure level from WeatherNext specific humidity, temperature and pressure. Native specific humidity is not exposed as a selectable API variable. |
| Low cloud cover | Derived from relative humidity at 1000, 925 and 850 hPa. |
| Mid cloud cover | Derived from relative humidity at 700, 600, 500 and 400 hPa. |
| High cloud cover | Derived from relative humidity at 300, 250, 200, 150, 100 and 50 hPa. |
| Total cloud cover | Calculated by combining the derived low, mid and high cloud layers. |
| Wind speed and direction | Calculated from the native U and V wind components. |
| Dew point and pressure-level cloud cover | Calculated by the API from pressure-level temperature and relative humidity. |
| Rain, snowfall and weather code | Estimated from total precipitation, temperature and the derived cloud information. WeatherNext does not predict these fields directly. |
Cloud cover is an estimate based on the vertical humidity profile. It is not a native cloud fraction forecast from WeatherNext.
API Documentation
Use the endpoint /v1/ensemble with models=google_weathernext2_ensemble. The tables below describe the variables specific to this model. Refer to the general Ensemble API documentation for URL parameters, response formats and the naming of individual ensemble members.
Hourly Parameter Definition
The API uses the common &hourly= parameter name. The table describes the default hourly output. WeatherNext provides native values every 6 hours, which the API interpolates to hourly time steps. Set temporal_resolution=native to return only the original 6-hour model intervals. At native resolution, precipitation is the accumulated sum of the preceding 6 hours; for hourly output, this total is distributed over the six corresponding hourly intervals while preserving the sum.
| Variable | Valid time | Unit | Description |
|---|---|---|---|
| temperature_2m sea_surface_temperature | Indicated hour | °C (°F) | Air temperature 2 m above ground and water temperature at the sea surface, interpolated from the 6-hourly model values. |
| pressure_msl surface_pressure | Indicated hour | hPa | Pressure at mean sea level and estimated pressure at the selected surface elevation, based on interpolated 6-hourly model values. |
| precipitation | Preceding hour sum | mm (inch) | Total liquid and frozen precipitation. Each native 6-hour accumulation is distributed over six hourly intervals. |
| rain snowfall snowfall_water_equivalent | Preceding hour sum | mm or cm (inch) | Rain and snowfall components derived from the hourly precipitation and temperature values. |
| cloud_cover cloud_cover_low cloud_cover_mid cloud_cover_high | Indicated hour | % | Cloud cover is derived from relative humidity at the native 6-hour timestamps and then interpolated for hourly output. |
| wind_speed_10m wind_speed_100m | Indicated hour | km/h (m/s, mph, knots) | Wind speed derived after interpolating the native U and V components. |
| wind_direction_10m wind_direction_100m | Indicated hour | ° | Wind direction derived after interpolating the native U and V components. |
| weather_code is_day | Indicated hour | WMO code / boolean | Weather code is derived from the hourly weather fields. Day-or-night status is calculated directly for every requested timestamp. |
Pressure-Level Parameter Definition
Append a supported pressure level to the variable name, for example temperature_500hPa or relative_humidity_850hPa. Native pressure-level fields are available at 6-hour intervals and are interpolated for the default hourly output.
| Variable pattern | Unit | Description |
|---|---|---|
| temperature_*hPa | °C (°F) | Air temperature interpolated from native 6-hourly pressure-level values. |
| relative_humidity_*hPa dew_point_*hPa | % / °C (°F) | Relative humidity is interpolated from the 6-hourly derived values. Dew point is calculated from hourly temperature and relative humidity. |
| cloud_cover_*hPa | % | Estimated for each hour from the interpolated relative humidity. |
| wind_speed_*hPa wind_direction_*hPa | km/h (m/s, mph, knots) / ° | Wind speed and direction derived after interpolating native U and V components. |
| vertical_velocity_*hPa | km/h (m/s, mph, knots) | Geometric vertical velocity interpolated from 6-hourly values. |
| geopotential_height_*hPa | m | Height of the selected pressure surface above mean sea level, interpolated from 6-hourly values. |
Daily Parameter Definition
Daily values are calculated from the 6-hourly forecast steps within the selected timezone. The available parameters include mean, minimum and maximum 2 m temperature; precipitation, rain and snowfall sums; precipitation hours; mean, minimum and maximum wind speed at 10 m and 100 m; dominant wind direction; mean, minimum and maximum cloud cover; and mean, minimum and maximum mean-sea-level and surface pressure. Select a timezone when requesting daily data so that the aggregation matches the intended local calendar day.