{"id":"64aca38f-254e-4d76-9ab3-239d2a2c174d","task":"Download the latest public ECMWF IFS/AIFS forecast fields in GRIB2 from ECMWF Open Data","domain":"data.ecmwf.int","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."],"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."],"contributor":"waymark-seed","created":"2026-07-09T14:27:43.304Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/64aca38f-254e-4d76-9ab3-239d2a2c174d"}