Single Runs API
Access any individual model run by initialisation time — ECMWF IFS from March 2024, all other models from September 2025.
Data Sources
Weather models are initialised and computed multiple times per day. Each run ingests the latest observations — radiosondes, weather stations, aircraft, satellites, and ocean buoys — and produces a complete forecast out to the model's full horizon (typically 7–16 days). The operational Open-Meteo Forecast API stitches the most recent run of each model into a seamless, continuously updated time-series. That approach is ideal for end-user applications but discards the individual run structure required for research, post-processing, and backtesting workflows.
The Single Runs API preserves this structure. Each run is stored and retrievable independently, so you can request the exact forecast issued at a specific initialisation time. The &run= parameter identifies the run by its UTC initialisation datetime, e.g. &run=2025-09-01T00:00.
The &run= parameter specifies the model's initialisation time — the UTC reference time at which the observations are taken — not the time at which the forecast output becomes publicly available. After initialisation, the model requires additional computation time before results are distributed: typically 4–6 hours for global models (e.g. ECMWF IFS, GFS) and 1–3 hours for regional models. This means a run initialised at 00 UTC is generally accessible from approximately 04–06 UTC onwards. The exact availability times for each model are listed on the model updates page.
Archival runs are available from September 2025 for most models. ECMWF IFS HRES at native 9 km resolution is available from March 14, 2024 (IFS Cycle 49R1 hindcasts). From May 12, 2026 06 UTC, runs use the updated IFS Cycle 50R1. ECMWF IFS HRES is the highest-quality global weather model and the backbone of the Open-Meteo Historical Weather API. Access to individual ECMWF runs is particularly valuable for renewable energy forecasting, where the full forecast horizon from a single run drives production scheduling and trading decisions.
| Weather Provider | Model | Region | Resolution | Temporal Resolution | Forecast Horizon | Run Frequency | Available From |
|---|---|---|---|---|---|---|---|
| ECMWF | IFS HRES 9 km | Global | 9 km (O1280 grid) | Hourly | 10 days | 4× daily (00, 06, 12, 18 UTC) | 2024-03-14 |
| Others | - | Global & Regional | up to 1 km | up to 15 minutely | up to 16 days | - | 2025-09-01 |
API Endpoint
The API endpoint https://single-runs-api.open-meteo.com/v1/forecast accepts the same parameters as the Weather Forecast API, with one additional required parameter: run. All weather variables, units, and output formats available in the Forecast API are supported. Data is served from a dedicated archive storage system, so response times may be higher than the real-time forecast API.
| Parameter | Format | Required | Default | Description |
|---|---|---|---|---|
| run | ISO 8601 datetime | Yes | The initialisation date and time of the model run to retrieve. Must be provided in ISO 8601 format without seconds, e.g. &run=2024-06-01T00:00. The time must correspond to a valid run cycle for the selected model (e.g. 00, 06, 12, 18 UTC for most global models). Runs that are not available will return an error. |
All other parameters from the Forecast API — including latitude, longitude, hourly, daily, and others — are also accepted unchanged. Please refer to the Weather Forecast API documentation for a complete parameter reference.