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NCI is now mananging the official replica for this dataset. The data in ub4 is not anymore available, we removed access and we will delete the actual files in June.

For any information on the new collection and transition: ERA5 Community site. For any direct enquiry: .

NB. any enquiry via the CWS helpdesk will have to be transferred to the right queue and would be delayed!

ERA5 is a climate reanalysis dataset, covering the period 1950 to present. ERA5 is being developed through the Copernicus Climate Change Service (C3S).

You can use the ERA5 Explorer tool to get a preview of the data (only few variables currently available). Or you can use the CDS toolbox to do some of your analysis without download the data. As descirbed on the CDS website the toolbox is "Free and available to everyone, the Toolbox links raw data to online computing power through a programming interface. In your own online workspace you can create applications in Python (a programming language) and run them on the CDS computers, allowing you to retrieve the data you are interested in, make the calculations you require and display the results in the format that suits your needs. You can download graphs, maps and data, and also share your online creations with other users."

Data processing for ERA5 is carried out by ECMWF, using ECMWFS' Earth System model IFS, cycle 41r2. The name ERA refers to 'ECMWF ReAnalysis', with ERA5 being the fifth major global reanalysis produced by ECMWF (after FGGE, ERA-15, ERA-40, ERA-Interim). The next reanalysis, ERA6, is planned for around 2020.

For more information on ERA5 data refer to the ECMWF ERA5 documentation.

For more specific information on ERA5 Land: ECMWF ERA5 Land documentation.

ERA5 derived products

Recently ECMWF has released new ERA5 derived products. These ranged from new variables calculated from ERA5 as for the fire indices or bias -corrected, interpolated versions of ERA5 main variables themselves. For a list check the Copernicus CDS.

CEMS-Fire - Fire danger indices historical data from the Copernicus Emergency Management Service

This ERA5 derived product was recently added to the Climate Data Store. It provides complete historical reconstruction of meteorological conditions favourable to the start, spread and sustainability of fires. The fire danger metrics provided are part of a vast dataset produced by the Copernicus Emergency Managment Service for the European Forest Fire Information System (EFFIS). The European Forest Fire Information System incorporates the fire danger indices for three different models developed in Canada, United States and Australia. In this dataset the fire danger indices are calculated using weather forecast from historical simulations provided by ECMWF ERA5 reanalysis (see more on CDS website). They have a daily temporal resolution on a 0.25X0.25 degrees grid. Currently they're available for the same period as ERA5 1979 to present.

WFDE5 - Near surface meteorological variables from 1979 to 2018 derived from bias-corrected reanalysis

This dataset provides bias-corrected reconstruction of near-surface meteorological variables derived from the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalyses (ERA5). It is intended to be used as a meteorological forcing dataset for land surface and hydrological models (see more on the CDS website).


Known Issues

Known issues from ECMWF website

Issue affecting WFDE5 v1.0  "Surface downwelling shortwave radiation" data. This is resolved in v1.1.

Dec 7 2018: an error has been discovered affecting the values of the following variables

CDS Dataset ERA5 hourly data on pressure levels from 2000 to present]
Parameters affected U-component of wind, V-component of wind
Level All pressure levels
Time periods affected 01 Jan. 2000 - 31 Dec. 2008
01 Jun. 2018 - present

This problem was caused by the computation of U/V from Vorticity (Vo) and Divergence (D) already interpolated onto a regular grid in CDS. U/V should have been computed from Vo and D in the spherical harmonics representation (the native model representation) and then interpolated to a regular grid before saving to the climate data store.

The problem is now fixed and we have re-downloading the data, download should be completed by the 19 March 2019. From the CDS communication: "During our investigations, we found that wind values are far too low on pressure levels at the poles in CDS, which has been documented as a known issue. Please use winds at neighbouring locations at 89.75 (N/S) and 89.5 (N/S) for Reanalysis and Ensemble members winds instead of 90 (N/S)."

Issues and other feedback shared by users: you can check this page for issues and other information shared by other users of ERA5, feel free to add your own contribution.


ERA5 data is open access and free to download for all uses, including commercial use. As for ERAI and other ECMWF datasets, though, you need to register with ECMWF and accept their terms and conditions, in this particular case ERA5 is covered by the Copernicus license


Note on forecasts

Forecasts are accumulated values defined at 20 steps (0-19) starting from times 06.00 and 18.00.

The accumulations are over the hour ending at the forecast step which is a different behaviour from era interim. The 0 step is always zero because it would be the accumulation from timestep and timestep +0 hours (I.e. 06.00 to 06.00)

The others would be for example for precipitation: Time 06.00 Step 1: forecast of accumulated precipitation between 06.00-07.00 Time 06.00 Step 19: forecast of accumulated precipitation between 06.00-01.00+1 day