# EPT-2 Family

Jua's flagship state-of-the-art weather model was first released in April 2025. The EPT-2 family outperforms leading public AI weather models including Microsoft Aurora, DeepMind's GraphCast, ECMWF's AIFS, and our previous EPT-1.5 model.

* **EPT-2**: Our deterministic model for precise weather forecasting
* **EPT-2 Early**: Our early-dissemination model delivering forecasts ahead of the market
* **EPT-2e**: Our ensemble model for probabilistic weather forecasting, especially for the long term
* **EPT-2 RR**: Our rapid-refresh model for hourly global weather intelligence
* **EPT-2 HRRR**: Our high-resolution rapid-refresh model
* **EPT-2 Reasoning**: Our AI weather forecast model with active learning from live data

For more information on our EPT-2 family of models, take a look at our [EPT-2 Technical Report](https://arxiv.org/abs/2507.09703).

## EPT-2 Family Comparison

<table><thead><tr><th>Model</th><th>Update Frequency</th><th>Ensemble<select><option value="bWyG2zvUpykn" label="Yes" color="blue"></option><option value="5ME4rgE38zxn" label="No" color="blue"></option></select></th><th>Forecast Horizon</th><th data-type="checkbox">Global coverage</th></tr></thead><tbody><tr><td>EPT-2</td><td>4 updates/day</td><td><span data-option="5ME4rgE38zxn">No</span></td><td>20 days</td><td>true</td></tr><tr><td>EPT-2 Early</td><td>4 updates/day</td><td><span data-option="5ME4rgE38zxn">No</span></td><td>20 days</td><td>true</td></tr><tr><td>EPT-2e</td><td>4 updates/day + 1 daily 60 day</td><td><span data-option="bWyG2zvUpykn">Yes</span></td><td>60 days</td><td>true</td></tr><tr><td>EPT-2 RR</td><td>24 updates/day</td><td><span data-option="5ME4rgE38zxn">No</span></td><td>2 days</td><td>true</td></tr><tr><td>EPT-2 HRRR</td><td>24 updates/day</td><td><span data-option="bWyG2zvUpykn">Yes</span></td><td>2 days</td><td>false</td></tr><tr><td>EPT-2 Reasoning</td><td>4 updates/day</td><td><span data-option="5ME4rgE38zxn">No</span></td><td>20 days</td><td>true</td></tr></tbody></table>

## Live Forecast Data

* Global coverage for EPT-2, EPT-2 Early, EPT-2e, and EPT-2 RR
* European coverage for EPT-2 HRRR
* Four daily runs (00, 06, 12, 18 UTC) for EPT-2, EPT-2 Early, EPT-2e
* 24 hourly runs for EPT-2 RR and EPT-2 HRRR
* 2-day prediction horizon (EPT-2 RR, EPT-2 HRRR)
* 20-day prediction horizon (EPT-2, EPT-2 Early, EPT-2e)
* 60-day prediction horizon for the EPT-2e forecast at 00 UTC
* Real-time data access via [Python SDK](https://docs.jua.ai/python-sdk/weather/forecast) or [REST API](https://docs.jua.ai/api-v2/getting-started)

## Technical Specifications

### Coordinates

| **Name**              | **Description**                           | **Units**           |
| --------------------- | ----------------------------------------- | ------------------- |
| init\_time            | Initialization time of forecast at UTC    | Absolute time (UTC) |
| prediction\_timedelta | Lead time relative to initialization time | Timedelta           |
| latitude              | Latitudinal coordinate                    | Degrees true        |
| longitude             | Longitudinal coordinate                   | Degrees true        |

### Spatial Extent

<table><thead><tr><th width="120.3515625">Model</th><th width="120.01953125">Latitudes</th><th width="120.44140625">Longitudes</th><th width="174.859375">Grid Size</th><th>Resolution</th></tr></thead><tbody><tr><td>EPT-2</td><td>[90, -90)</td><td>[-180, 180)</td><td>2160x4320</td><td>0.081° (9 km)</td></tr><tr><td>EPT-2 Early</td><td>[90, -90)</td><td>[-180, 180)</td><td>1440x2880</td><td>0.125° (12 km)</td></tr><tr><td>EPT-2e</td><td>[90, -90)</td><td>[-180, 180)</td><td>720x1440</td><td>0.25° (25 km)</td></tr><tr><td>EPT-2 RR</td><td>[90, -90)</td><td>[-180, 180)</td><td>720x1440</td><td>0.25° (25 km)</td></tr><tr><td>EPT-2 HRRR</td><td>[36, 72]</td><td>[-15, 45]</td><td>721x1201</td><td>0.05° (5.5 km)</td></tr><tr><td>EPT-2 Reasoning</td><td>[90, -90)</td><td>[-180, 180)</td><td>2160x4320</td><td>0.081° (9 km)</td></tr></tbody></table>

### Available Weather Parameters

EPT-2 uses standardized variable naming conventions. For full details on the naming structure, see [Weather Variable Naming](https://docs.jua.ai/python-sdk/weather/naming).

{% hint style="info" %}
Wind speed at additional heights (20m, 40m, 60m, 80m, 120m, 140m, 160m, 180m, 200m) and air density at 2m are available from **March 1, 2026** onwards.
{% endhint %}

<table data-full-width="false"><thead><tr><th width="101.25390625">Code</th><th width="362.796875">API Name</th><th width="180.859375">Description</th><th>Units</th></tr></thead><tbody><tr><td>2t</td><td>air_temperature_at_height_level_2m</td><td>Air temperature at 2m</td><td>Kelvin</td></tr><tr><td>2d</td><td>dew_point_temperature_at_height_level_2m</td><td>Dew point temperature at 2m</td><td>Kelvin</td></tr><tr><td>r</td><td>relative_humidity_at_height_level_2m</td><td>Relative humidity at 2m</td><td>%</td></tr><tr><td>10si</td><td>wind_speed_at_height_level_10m</td><td>Horizontal wind speed at 10m</td><td>m s⁻¹</td></tr><tr><td>10wdir</td><td>wind_direction_at_height_level_10m</td><td>Horizontal wind direction at 10m</td><td>Degrees true</td></tr><tr><td>100si</td><td>wind_speed_at_height_level_100m</td><td>Horizontal wind speed at 100m</td><td>m s⁻¹</td></tr><tr><td>100wdir</td><td>wind_direction_at_height_level_100m</td><td>Horizontal wind direction at 100m</td><td>Degrees true</td></tr><tr><td>20si</td><td>wind_speed_at_height_level_20m</td><td>Horizontal wind speed at 20m</td><td>m s⁻¹</td></tr><tr><td>40si</td><td>wind_speed_at_height_level_40m</td><td>Horizontal wind speed at 40m</td><td>m s⁻¹</td></tr><tr><td>60si</td><td>wind_speed_at_height_level_60m</td><td>Horizontal wind speed at 60m</td><td>m s⁻¹</td></tr><tr><td>80si</td><td>wind_speed_at_height_level_80m</td><td>Horizontal wind speed at 80m</td><td>m s⁻¹</td></tr><tr><td>120si</td><td>wind_speed_at_height_level_120m</td><td>Horizontal wind speed at 120m</td><td>m s⁻¹</td></tr><tr><td>140si</td><td>wind_speed_at_height_level_140m</td><td>Horizontal wind speed at 140m</td><td>m s⁻¹</td></tr><tr><td>160si</td><td>wind_speed_at_height_level_160m</td><td>Horizontal wind speed at 160m</td><td>m s⁻¹</td></tr><tr><td>180si</td><td>wind_speed_at_height_level_180m</td><td>Horizontal wind speed at 180m</td><td>m s⁻¹</td></tr><tr><td>200si</td><td>wind_speed_at_height_level_200m</td><td>Horizontal wind speed at 200m</td><td>m s⁻¹</td></tr><tr><td>2rho</td><td>air_density_at_height_level_2m</td><td>Air density at 2m</td><td>kg m⁻³</td></tr><tr><td>msl</td><td>air_pressure_at_mean_sea_level</td><td>Mean Sea-level Pressure</td><td>Pa</td></tr><tr><td>lcc</td><td>cloud_area_fraction_at_entire_atmosphere_low_type</td><td>Low Cloud Cover</td><td>%</td></tr><tr><td>mcc</td><td>cloud_area_fraction_at_entire_atmosphere_medium_type</td><td>Medium Cloud Cover</td><td>%</td></tr><tr><td>hcc</td><td>cloud_area_fraction_at_entire_atmosphere_high_type</td><td>High Cloud Cover</td><td>%</td></tr><tr><td>tp</td><td>precipitation_amount_sum_1h</td><td>Total Precipitation</td><td>mm m⁻²</td></tr><tr><td>ssrd</td><td>surface_downwelling_shortwave_flux_sum_1h</td><td>Surface solar downward irradiance</td><td>J m⁻²</td></tr><tr><td>fdir</td><td>surface_direct_downwelling_shortwave_flux_sum_1h</td><td>Direct solar radiation at the surface</td><td>J m⁻²</td></tr><tr><td>z_500</td><td>geopotential_at_pressure_level_50000Pa</td><td>Geopotential</td><td>m² s⁻²</td></tr></tbody></table>

Note: The previous naming convention used in EPT-1.5 is deprecated. All new integrations should use the standardized naming shown above.

#### EPT-2 HRRR

EPT-2 HRRR produces a subset of the EPT-2 variables.

| Parameter Code | API Name                                                    | Description                           | Units        |
| -------------- | ----------------------------------------------------------- | ------------------------------------- | ------------ |
| 2t             | air\_temperature\_at\_height\_level\_2m                     | Air temperature at 2m                 | Kelvin       |
| 2d             | dew\_point\_temperature\_at\_height\_level\_2m              | Dew point temperature at 2m           | Kelvin       |
| r              | relative\_humidity\_at\_height\_level\_2m                   | Relative humidity at 2m               | %            |
| 10si           | wind\_speed\_at\_height\_level\_10m                         | Horizontal wind speed at 10m          | m s⁻¹        |
| 10wdir         | wind\_direction\_at\_height\_level\_10m                     | Horizontal wind direction at 10m      | Degrees true |
| 100si          | wind\_speed\_at\_height\_level\_100m                        | Horizontal wind speed at 100m         | m s⁻¹        |
| 100wdir        | wind\_direction\_at\_height\_level\_100m                    | Horizontal wind direction at 100m     | Degrees true |
| 20si           | wind\_speed\_at\_height\_level\_20m                         | Horizontal wind speed at 20m          | m s⁻¹        |
| 40si           | wind\_speed\_at\_height\_level\_40m                         | Horizontal wind speed at 40m          | m s⁻¹        |
| 60si           | wind\_speed\_at\_height\_level\_60m                         | Horizontal wind speed at 60m          | m s⁻¹        |
| 80si           | wind\_speed\_at\_height\_level\_80m                         | Horizontal wind speed at 80m          | m s⁻¹        |
| 120si          | wind\_speed\_at\_height\_level\_120m                        | Horizontal wind speed at 120m         | m s⁻¹        |
| 140si          | wind\_speed\_at\_height\_level\_140m                        | Horizontal wind speed at 140m         | m s⁻¹        |
| 160si          | wind\_speed\_at\_height\_level\_160m                        | Horizontal wind speed at 160m         | m s⁻¹        |
| 180si          | wind\_speed\_at\_height\_level\_180m                        | Horizontal wind speed at 180m         | m s⁻¹        |
| 200si          | wind\_speed\_at\_height\_level\_200m                        | Horizontal wind speed at 200m         | m s⁻¹        |
| 2rho           | air\_density\_at\_height\_level\_2m                         | Air density at 2m                     | kg m⁻³       |
| msl            | air\_pressure\_at\_mean\_sea\_level                         | Mean Sea-level Pressure               | Pa           |
| lcc            | cloud\_area\_fraction\_at\_entire\_atmosphere\_low\_type    | Low Cloud Cover                       | %            |
| mcc            | cloud\_area\_fraction\_at\_entire\_atmosphere\_medium\_type | Medium Cloud Cover                    | %            |
| hcc            | cloud\_area\_fraction\_at\_entire\_atmosphere\_high\_type   | High Cloud Cover                      | %            |
| tp             | precipitation\_amount\_sum\_1h                              | Total Precipitation                   | mm m⁻²       |
| ssrd           | surface\_downwelling\_shortwave\_flux\_sum\_1h              | Surface solar downward irradiance     | J m⁻²        |
| fdir           | surface\_direct\_downwelling\_shortwave\_flux\_sum\_1h      | Direct solar radiation at the surface | J m⁻²        |

### Additional Variables on Request

| Parameter Code | API Name                                    | Description                                                            | Units  |
| -------------- | ------------------------------------------- | ---------------------------------------------------------------------- | ------ |
| tcwv           | atmosphere\_mass\_content\_of\_water\_vapor | Total column vertically-integrated water vapour                        | kg m⁻² |
| t              | air\_temperature\_at\_pressure\_level       | Temperature at a specified pressure level                              | K      |
| u              | eastward\_wind\_at\_pressure\_level         | U component of wind                                                    | m s⁻¹  |
| v              | northward\_wind\_at\_pressure\_level        | V component of wind                                                    | m s⁻¹  |
| q              | specific\_humidity\_at\_pressure\_level     | The mass of water vapour per kilogram of moist air at a pressure level | kg     |
| z              | geopotential\_at\_pressure\_level           | The gravitational potential energy of a unit mass                      | m² s⁻² |

* Pressure levels: 5'000, 10'000, 15'000, 20'000, 25'000, 30'000, 40'000, 50'000, 60'000, 70'000, 85'000, 92'500, 100'000

## Hindcast Data

**Data Access:** Hindcasts are available via our [Python SDK](https://docs.jua.ai/python-sdk/getting-started) and [API](https://docs.jua.ai/api-v2/getting-started). For large requests, please contact <support@jua.ai>.

| **Model**       | **Temporal Extent**                                                         | **Forecast Horizon and Resolution**                                                                                    |
| --------------- | --------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
| EPT-2           | <p>2023-01-01 - today</p><p>at 00, 06, 12, 18 UTC</p>                       | <p>480h</p><p>- From 1h to 240h: hourly</p><p>- From 240h to 480h: six-hourly</p>                                      |
| EPT-2e          | <p>2025-08-16 - today</p><p>at 00, 06, 12, 18 UTC</p>                       | <p>00 UTC: 1440h; 06, 12, 18 UTC: 480h</p><p>- From 1h to 240h: hourly</p><p>- From 240h to 480h/1440h: six-hourly</p> |
| EPT-2 RR        | <p>2024-01-01 04:00:00 - today</p><p>at 00-23 UTC (every hour)</p><p>\*</p> | 48h, hourly                                                                                                            |
| EPT-2 HRRR      | <p>2025-01-01 04:00:00 - today</p><p>at 00-23 UTC (every hour)</p><p>\*</p> | 48h, hourly                                                                                                            |
| EPT-2 Early     | <p>2025-09-01 - today</p><p>at 00, 06, 12, 18 UTC</p>                       | <p>480h</p><p>- From 1h to 240h: hourly</p><p>- From 240h to 480h: six-hourly</p>                                      |
| EPT-2 Reasoning | <p>2025-08-27 - today</p><p>at 00, 06, 12, 18 UTC</p>                       | <p>480h</p><p>- From 1h to 240h: hourly</p><p>- From 240h to 480h: six-hourly</p>                                      |

\* EPT-2 RR and EPT-2 HRRR have missing data on the 2025-10-20.

### Extended Hindcast Data (Special Request Only)

{% hint style="warning" %}
**Special Request Required**: The following extended hindcast data is available but requires special access permissions and is not accessible through standard API/SDK access. Please contact <support@jua.ai> to request access.
{% endhint %}

| **Model**   | **Extended Temporal Coverage**                                                      | **Forecast Horizon and Resolution**                                               |
| ----------- | ----------------------------------------------------------------------------------- | --------------------------------------------------------------------------------- |
| EPT-2 Early | <p>2024-03-01 - 2024-03-13, 2024-06-05 - 2024-12-31</p><p>at 00, 06, 12, 18 UTC</p> | <p>480h</p><p>- From 1h to 240h: hourly</p><p>- From 240h to 480h: six-hourly</p> |

## Performance Benchmarks

EPT-2 consistently outperforms other leading weather models, including:

* Microsoft Aurora
* DeepMind's GraphCast
* ECMWF's AIFS
* Our previous EPT-1.5 model

For more details on EPT-2 performance benchmarks, check out our [benchmarking analysis](https://jua.ai/products/benchmarks).

## Dissemination Times

For detailed dissemination times of the EPT-2 family please refer to the [Dissemination Times](https://docs.jua.ai/models-and-products/dissemination-times) page.