Calculate one or more forecast hours and return interpolated values for the requested geographic coordinates. Omit forecast_hours to calculate every available hour. See About Custom Calculations for calculation syntax and examples.
| Name | Type | Description |
|---|---|---|
| model Required | string | Weather model to use. Supported values are wm-6 and wm-6-3km . |
| initialization_time Optional | string | Forecast initialization time in ISO 8601 format. Omit it to use the latest complete update. |
| forecast_hours Optional | integer or integer[] | One nonnegative forecast hour or a nonempty list of nonnegative forecast hours. Omit to evaluate every available forecast hour. |
| calculation Required | string | Custom calculation expression to evaluate. See About Custom Calculations for syntax and examples. |
| coordinates Required | string | Latitude,longitude pairs separated by semicolons, such as 37.7749,-122.4194;34.0522,-118.2437 . Longitude uses the −180 to 180 convention. |
| Selection | Example | Behavior |
|---|---|---|
| One hour | "forecast_hours": 6 | Evaluate the calculation at forecast hour 6. |
| Specific hours | "forecast_hours": [0, 6, 12] | Evaluate the calculation at the listed forecast hours. |
| All hours | Omit forecast_hours | Evaluate the calculation at every available forecast hour. |
Each selected forecast hour is calculated separately. Hours that do not have all required input data are skipped, and results for the remaining hours are returned. If no selected hour can be calculated, the request returns HTTP 400.
| Field | Type | Description |
|---|---|---|
| model | string | The model used for the calculation. |
| initialization_time | string | The forecast initialization time used, in ISO 8601 format. |
| forecast_zero | string | The time the forecast starts. Forecast hours are counted from this time. It can differ from initialization_time . |
| forecast_hours | integer[] | The requested forecast hours, returned as an array. |
| calculation | string | The calculation evaluated by the request. |
| grid_calculations | string[] | The calculation for each output grid. grid_calculations[i] describes grids[i] in every successful forecast-hour result. |
| coordinates | string | The requested latitude,longitude pairs in request order. Every values array follows this order. |
| forecast_hour_errors | object[] | Requested forecast hours that could not be calculated. Empty when every requested hour succeeds. |
| forecast_hour | integer | The forecast hour that could not be calculated. |
| code | string | Machine-readable reason for the failure. |
| message | string | Human-readable description of the failure. |
| results | object[] | One result for each forecast hour that was calculated successfully. |
| forecast_hour | integer | The successfully calculated forecast hour. |
| grids | object[] | The calculated grids, in the same order as grid_calculations . |
| valid_from | string or null | The start of the grid's valid time range, in ISO 8601 format. |
| valid_to | string or null | The end of the grid's valid time range, in ISO 8601 format. |
| values | (number or null)[] | One calculated value for each latitude,longitude pair in coordinates , in the same order. Unavailable, outside-grid, and non-finite values are null . |
Forecast inputs keep their native units. The unit of each returned value depends on the calculation.