At ECMWF, many public datasets are available through both the Web interface and the ECMWF WebAPI, the programmatic way of retrieving data from the archive.

Some public datasets are only available through ECMWF's WebAPI. However, an archive catalogue called MARS catalogue is provided to users to help them browse through the archive tree and check the availability of parameters. The MARS catalogue browsing facility also provides sample WebAPI scripts to help users build their own scripts.


To be able to download data via the ECMWF WebAPI, you will need:

  1. An ECMWF account. If you don't have an account, please self register at https://apps.ecmwf.int/registration/

  2. A computer with a *nix operating system is highly recommended. Microsoft Windows is known to work too, but is unsupported.

  3. The Python programming language. If you do not have it installed yet, install Python now. In practice, you can download the data without knowing how Python works! We provide step-by-step instructions for each dataset listed in 5.

  4. To configure your computer to programmatically retrieve data from ECMWF, by following the 2 steps described below. You only need to do this once, and only if you have never retrieved ECMWF data using Python before:
    1. Install ECMWF Key
    2. Install the ECMWF WebAPI client library

  5. To follow the WebAPI download instructions specific to the dataset of interest:

Feedback: C3S User Satisfaction Survey - CAMS User Satisfaction Survey

Web: C3S Help and Support - CAMS Help and Support