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The data are archived in the ECMWF data archive MARS and datasets are available until 31 May 2023 through both the ECMWF Web interface and the ECMWF WebAPI, which is the programmatic way of retrieving data from the archive.
Until further notice, ERA-Interim is also available via the API of the C3S Climate Data Store.
Documentation is available on How to download ERA-Interim data from the ECMWF data archive (Member State users can access the data directly from MARS, in the usual manner).
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