DWD ICON Weather Model Archive

Archives of NWP data from Germany's National Meteorological Service, the Deutscher Wetterdienst (DWD).

DWD maintains only a 24-hour rolling window of files on their servers, some of which we archive here.

The files are in GRIB (GRIdded Binary) Edition 2 (GRIB2) format, compressed with bzip2. We currently archive GRIB2 files from DWD's ICON-EU model. For ICON-EU, we archive all vertical model levels, and all NWP variables, for 4 NWP runs per day (the runs initialised at 00, 06, 12, and 18 UTC). Each file is copied without modification from DWD. Each model run consists of 77,805 files, totalling about 59 GiB or 86 TiB per year. We do not archive the pressure level files.

This archive on Source Cooperative is updated four times per day.

Individual files are added to the archive atomically (thanks to the atomicity guarantees of cloud object storage). So you should never see an incomplete file. In contrast, directories are not updated atomically. If you read the directory for the most recent NWP run then the directory may be incomplete.

A subset of the variables in these files will be available in a cloud-optimized Icechunk Zarr format, see dynamical.org for availability.

To avoid having single directories with millions of files, we use a slightly different directory structure to DWD's directory structure. Our directory structure is:

• NWP model name
• Spatial grid
• UTC NWP initialization datetime in YYYY-MM-DDTHH format
• NWP variable name
• Filename {prefix}_{init time}_{lead time hour}_{NWP variable name}.grib2.bz2

For example: https://data.source.coop/dynamical/dwd-icon-grib/icon-eu/regular-lat-lon/2026-02-11T00/t_2m/icon-eu_europe_regular-lat-lon_single-level_2026021100_001_T_2M.grib2.bz2

The code that copies the files from DWD to this repository is available on GitHub. This code was written with support from Open Climate Fix, funded by a grant from the Patrick J McGovern Foundation. The compute to transfer the files is provided by dynamical.org.

Data license: Creative Commons BY 4.0. To quote DWD's legal notice:

All freely accessible geodata and geodata services, as well as DWD services defined as high-value datasets (HVD), may be reused under the terms of the Creative Commons BY 4.0 (CC BY 4.0) license, provided the source is acknowledged. Geodata includes all provided meteorological weather and climate information with a location reference.