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ERA-Interim production stopped on 31st August 2019

For the time being and until further notice, ERA-Interim (1st January 1979 to 31st August 2019) shall continue to be accessible through the ECMWF Web API. Keeping in mind that ERA-Interim is published with an offset of about three months from the dataset's reference date, ERA-Interim August 2019 data will be made available towards the end of October 2019.

ERA5 is now available from the Climate Data Store (CDS) (What are the changes from ERA-Interim to ERA5?) and users are strongly advised to migrate to ERA5 (How to migrate from ECMWF Web API to CDS API).


The observations assimilated in ERA-Interim are described in Section 4: "Observations" of an article on the ERA-Interim reanalysis in the Quarterly Journal of the Royal Meteorological Society.


The overwhelming majority of data originate from satellites.


  • For upper-air temperatures, wind and specific humidity, observations from satellites, radiosondes, pilot balloons, aircraft, and wind profilers were assimilated.
  • For surface pressure, 2m temperature, and 2m relative humidity, observations from ships, drifting buoys, and land stations were assimilated.
  • For near-surface (10 m) winds, only observations over sea were assimilated, coming from scatterometers, ships and buoys.


ERA-Interim assimilates only data that is supplied through the WMO GTS, and there only data that

  • is supplied in in near-real-time
  • meets certain quality criteria and file format standards

Regarding data from field campaigns, in case campaign data was supplied to the GTS in near-real-time, and meets the relevant data format standards, the data was assimilated. We have no records of individual campaign's names or acronyms though.