WeatherNext Gen (GenCast) is a probabilistic ensemble forecasting model developed by Google DeepMind and Google Research. It uses a conditional diffusion architecture coupled with a graph neural network and graph transformer to generate an ensemble of 50 possible weather trajectories, capturing forecast uncertainty. In evaluations, GenCast outperformed ECMWF's ENS (the leading operational ensemble system) in over 96% of targets, with a 6–12 hour lead time advantage for tropical cyclone tracking. The model is particularly well suited for uncertainty quantification and extreme event prediction. For more, see the DeepMind blog post.
At a glance
| Attribute | Details |
|---|---|
| Coverage | Global |
| Spatial Resolution | 0.25° (~30 km at the equator) |
| Temporal Resolution | 12 hours |
| Forecast Horizon | 15 days |
| Initialization Frequency | Every 6 hours (00, 06, 12, 18 UTC) |
| Forecast Type | Ensemble (50 members) |
| Architecture | Conditional diffusion model with GNN + graph transformer (paper) |
| Training Data | ERA5 / HRES-fc0 |
| Initialization Inputs | HRES-fc0 |
| Historical Forecasts | 2020 – present |
Supported variables
Surface variables
| Variable Name | Description | Units |
|---|---|---|
2m_temperature |
2 metre temperature | K |
10m_u_component_of_wind |
10 metre U (eastward) wind component | m/s |
10m_v_component_of_wind |
10 metre V (northward) wind component | m/s |
100m_u_component_of_wind |
100 metre U (eastward) wind component | m/s |
100m_v_component_of_wind |
100 metre V (northward) wind component | m/s |
mean_sea_level_pressure |
Mean sea level pressure | Pa |
total_precipitation |
Total precipitation (12-hour accumulated) | m |
sea_surface_temperature |
Sea surface temperature | K |
Atmospheric variables (pressure levels)
These variables are available at 13 pressure levels: 50, 100, 150, 200, 250, 300, 400, 500, 600, 700, 850, 925, 1000 hPa.
| Variable Name | Description | Units |
|---|---|---|
{level}_geopotential |
Geopotential height | m2/s2 |
{level}_specific_humidity |
Specific humidity | kg/kg |
{level}_temperature |
Temperature | K |
{level}_u_component_of_wind |
U (eastward) wind component | m/s |
{level}_v_component_of_wind |
V (northward) wind component | m/s |
{level}_vertical_velocity |
Vertical velocity | Pa/s |
Replace {level} with the pressure level in hPa. For example,
500_geopotential for geopotential at 500 hPa.
See the Glossary for definitions of meteorological terms.
How to access
WeatherNext Gen datasets on BigQuery and Earth Engine were deprecated on July 29, 2026. Users previously on the allowlist for Gen automatically have access to WeatherNext 3 datasets. See the deprecation page for migration details and WeatherNext 3 for current operational forecasts.