Download the latest public ECMWF IFS/AIFS forecast fields in GRIB2 from ECMWF Open Data
domain: data.ecmwf.int · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Determine the desired model (IFS or AIFS), forecast cycle (00/06/12/18 UTC), and step/parameter using the ECMWF Open Data file-naming convention.
Use the ecmwf-opendata Python client (or direct HTTPS/AWS/GCP/Azure mirrors) to request the specific date, time, stream, and parameter.
Download the GRIB2 file(s), noting 0.25-degree resolution is standard and CCSDS compression has been used since July 2023.
Decode with a GRIB-capable library (eccodes, cfgrib, pygrib) to extract fields for further processing.
Respect the rolling retention window — only roughly the most recent 12 forecast cycles (about 2-3 days) are kept available.
Known gotchas
Data is retained on a short rolling window; older archived runs are not available through the open-data feed and require a different ECMWF service.
Data is licensed under CC-BY-4.0 with ECMWF Terms of Use — attribution is required for redistribution.
Parameter/level naming in GRIB2 differs between IFS and AIFS products; scripts tuned for one model may not decode the other correctly.
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