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European Centre for Medium-Range Weather Forecasts
Established1975 Edit this on Wikidata (49 years ago)
HeadquartersReading Edit this on Wikidata
CountryUnited Kingdom Edit this on Wikidata
Coordinates51°25′11″N 0°57′03″W / 51.41961°N 0.95081°W / 51.41961; -0.95081 Edit this at Wikidata
Chief ExecutivesFlorence Rabier Edit this on Wikidata
DirectorsFlorence Rabier Edit this on Wikidata

The European Centre for Medium-Range Weather Forecasts (ECMWF) is an independent intergovernmental organisation supported by most of the nations of Europe. It is based at three sites: Shinfield Park, Reading, United Kingdom; Bologna, Italy; and Bonn, Germany. It operates one of the largest supercomputer complexes in Europe and the world's largest archive of numerical weather prediction data.[1]


  members as of 2015
  co-operation agreement

ECMWF was established in 1975, in recognition of the need to pool the scientific and technical resources of Europe's meteorological services and institutions for the production of weather forecasts for medium-range timescales (up to approximately two weeks) and of the economic and social benefits expected from it. The Centre employs about 350 staff, mostly appointed from across the member states and co-operating states.[1]

An aerial photograph of the ECMWF building in Bologna, surrounded by roads and residential buildings.
Aerial view of the data centre in Bologna, Italy.

In 2017, the centre's member states accepted an offer from the Italian Government to move ECMWF's data centre to Bologna, Italy.[2] The new site, a former tobacco factory, would be redesigned by the architecture firm gmp.

During 2020, the Centre arranged to move its Copernicus operations away from Reading and into European Union territory.[3] Following bids from Toulouse,[3] Italy,[4] Austria,[5] Germany,[6] Spain[7] and Ireland,[8] eventually Bonn (Germany) was chosen.[9] The move has been directly attributed to Brexit.[9][10]

In August 2023, the centre partnered with Huawei on its cloud, AI-powered Pangu-Weather model for 10-day global weather prediction accuracies.[11]


ECMWF aims to provide accurate medium-range global weather forecasts out to 15 days and seasonal forecasts out to 12 months.[12] Its products are provided to the national weather services of its member states and co-operating states as a complement to their national short-range and climatological activities, and those national states use ECMWF's products for their own national duties, in particular to give early warning of potentially damaging severe weather.

ECMWF's core mission is to:[13]

To deliver this core mission, the Centre provides:

The Centre develops and operates global atmospheric models and data assimilation systems for the dynamics, thermodynamics and composition of the Earth's atmosphere and for interacting parts of the Earth-system. It uses numerical weather prediction methods to prepare forecasts and their initial conditions, and it contributes to monitoring the relevant parts of the Earth system.

Work and projects


Numerical weather prediction (NWP) requires input of meteorological data, collected by satellites and earth observation systems such as automatic and crewed weather stations, aircraft (including commercial flights[14]), ships and weather balloons. Assimilation of this data is used to produce an initial state of a computer model of the atmosphere, from which an atmospheric model is used to forecast the weather. These forecasts are typically:

Over the past three decades ECMWF's wide-ranging programme of research has played a major role in developing such assimilation and modelling systems. This improves the accuracy and reliability of weather forecasting by about a day per decade, so that a seven-day forecast now (2015) is as accurate as a three-day forecast was four decades ago (1975).[15]

Monthly and seasonal forecasts

ECMWF's monthly and seasonal forecasts provide early predictions of events such as heat waves, cold spells and droughts, as well as their impacts on sectors such as agriculture, energy and health. Since ECMWF runs a wave model, there are also predictions of coastal waves and storm surges in European waters which can be used to provide warnings.

Early warning of severe weather events

Forecasts of severe weather events allow appropriate mitigating action to be taken and contingency plans to be put into place by the authorities and the public. The increased time gained by issuing accurate warnings can save lives, for instance by evacuating people from a storm surge area. Authorities and businesses can plan to maintain services around threats such as high winds, floods or snow.

In October 2012 the ECMWF model suggested seven days in advance that Hurricane Sandy was likely to make landfall on the East Coast of the United States.[16] It also predicted the intensity and track of the November 2012 nor'easter, which impacted the east coast a week after Sandy.[17]

ECMWF's Extreme Forecast Index (EFI) was developed as a tool to identify where the EPS (Ensemble Prediction System) forecast distribution differs substantially from that of the model climate[clarification needed]. It contains information regarding variability of weather parameters, in location and time and can highlight an abnormality of a weather situation without having to define specific space- and time-dependent thresholds.

Satellite data

ECMWF, through its partnerships with EUMETSAT, ESA, the EU and others, exploits satellite data for operational numerical weather prediction and operational seasonal forecasting with coupled atmosphere–ocean–land models. The increasing amount of satellite data and the development of more sophisticated ways of extracting information from that data have made a major contribution to improving the accuracy and utility of NWP forecasts.[citation needed] ECMWF continuously endeavours to improve the use of satellite observations for NWP.


Main article: ECMWF re-analysis

ECMWF supports research on climate variability using an approach known as reanalysis. This involves feeding weather observations collected over decades into a NWP system to recreate past atmospheric, sea- and land-surface conditions over specific time periods to obtain a clearer picture of how the climate has changed. Reanalysis provides a four-dimensional picture of the atmosphere and effectively allows monitoring of the variability and change of global climate, thereby contributing also to the understanding and attribution of climate change.

To date, and with support from Europe's National Meteorological Services and the European Commission, ECMWF has conducted several major reanalyses of the global atmosphere: the first ECMWF re-analysis (ERA-15) project generated reanalyses from December 1978 to February 1994; the ERA-40 project generated reanalyses from September 1957 to August 2002. The ERA-Interim reanalysis[18] covered the period from 1979 onwards. A reanalysis product (ERA5)[19] with higher spatial resolution (31 km) was released by ECMWF in 2019 as part of the Copernicus Climate Change Service.[20]

Operational forecast model

Main article: Integrated Forecast System

ECMWF's operational forecasts are produced from its "Integrated Forecast System" (sometimes informally known in the United States as the "European model") which is run every twelve hours and forecasts out to ten days.

It includes both a "deterministic forecast" mode and an ensemble. The deterministic forecast is a single model run that is relatively high in resolution as well as in computational expense. The ensemble is relatively low (about half that of the deterministic) in resolution (and in computational expense), so less accurate. But it is run 51 times in parallel, from slightly different initial conditions to give a spread of likelihood over the range of the forecast.[21]

As of 2021, the ECMWF's weather model is generally considered to be the most accurate weather forecasting model.[22]


The centre currently serves as the Entrusted Entity responsible for delivery of two of the Services of the EU's Copernicus Programme. The two services are the Copernicus Atmosphere Monitoring Service (CAMS)[23] and the Copernicus Climate Change Service (C3S).[24]

The Centre arranged to move its Copernicus operations away from Reading and into Bonn (Germany).[3][9] The move has been directly attributed to Brexit.[9][10]

Member and co-operating states

ECMWF comprises 23 European countries:

It also has co-operation agreements with other states: Bulgaria, Czech Republic, Georgia, Hungary, Israel, Latvia, Lithuania, North Macedonia, Montenegro, Morocco, Romania and Slovakia.

Member state[30] Year of joining
 Austria 1975
 Belgium 1975
 Croatia 2011
 Denmark 1975
 Estonia 2020
 Finland 1975
 France 1975
 Germany 1975
 Greece 1976
 Iceland 2011
 Ireland 1975
 Italy 1977
 Luxembourg 2002
 Netherlands 1975
 Norway 1989
 Portugal 1976
 Serbia 2014
 Slovenia 2011
 Spain 1975
 Sweden 1975
  Switzerland 1975
 Turkey 1976
 United Kingdom 1975
Co-operating State[31] Year of joining
 Bulgaria 12 July 2010
 Czech Republic 1 August 2001
 Georgia 1 December 2021
 Hungary 1 July 1994
 Israel 28 October 2010
 Latvia 30 April 2008
 Lithuania 20 November 2006
 Montenegro 5 November 2007
 Morocco 1 December 2006
 North Macedonia 9 February 2011
 Romania 22 December 2003
 Slovakia 1 January 2008
Co-operating agreements[32] Year of joining
WMO 1 November 1975
EUMETSAT 18 May 1988
ACMAD 11 May 1995
ALADIN/HIRLAM - Use of IFS/Arpege 19 February 1999
JRC 6 May 2003
CTBTO 24 June 2003
CLRTAP 26 January 2005
ESA 31 May 2005
Memorandum of Understanding for Joint Liaison Office with European institutions in Brussels 23 April 2010
RIMES 8 February 2012
CMA 21 January 2014
US NWS 23 January 2015 - amended 30 January 2018
US NCAR 31 August 2016
INPE Brazil 31 August 2017

See also


  1. ^ a b "Who we are". ECMWF. 28 November 2013. Retrieved 1 January 2016.
  2. ^ "Press kit: Bologna to host ECMWF's new data centre". 3 March 2017.
  3. ^ a b c "France Applies to Host Top Weather Forecaster Now Based in U.K." Bloomberg. 30 May 2020.
  4. ^ "Tecnopolo di Bologna. Il Governo autorizza la spesa di 40 milioni nel prossimo triennio, di cui 10 milioni nel 2020". CONFERENZA DELLE REGIONI E DELLE PROVINCE AUTONOME. 20 May 2020. Retrieved 18 June 2020.
  5. ^ "Regierung will Klimawandel-Überwachungsdienst nach Österreich holen". Die Presse. 20 May 2020. Retrieved 18 June 2020.
  6. ^ "SO WILL BONN EUROPÄISCHES WETTER-ZENTRUM WERDEN!". TAG24. 16 June 2020. Retrieved 18 June 2020.
  7. ^ "España postulará a Barcelona como sede del Centro Europeo de Predicciones Meteorológicas a Plazo Medio". europa press. 29 May 2020. Retrieved 18 June 2020.
  8. ^ "Govt to bid for relocation of EU forecaster from UK to Ireland". Radió Telefis Éireann. 23 September 2020. Retrieved 24 September 2020.
  9. ^ a b c d ""European weather authority relocates to Bonn"". City of Bonn. 9 December 2020. Archived from the original on 16 December 2020. Retrieved 9 December 2020.
  10. ^ a b "European Center for Weather Forecasting: France selects Toulouse candidate". en24 news. 30 May 2020. Retrieved 1 June 2020.
  11. ^ SYMONDS, DAN. "Huawei Cloud launches AI-powered Pangu-Weather model". Meteorological Technology International. Meteorological Technology International. Retrieved 13 February 2024.
  12. ^ Deutscher Wetterdienst. "ECMWF - European Centre for Medium-Range Weather Forecasts". Berlin, Germany: Federal Ministry of Transport and Digital Infrastructure. Retrieved 29 April 2014. Established in 1975, ECMWF is renowned worldwide for providing the most accurate medium-range global weather forecasts up to 10 days ahead, monthly forecasts and seasonal outlooks to six months ahead.
  13. ^ ECMWF (30 December 2013), What we do, retrieved 11 June 2019
  14. ^ "COVID-19: Aeolus and weather forecasts". Retrieved 30 July 2023.
  15. ^ "The Forecast For Weather Technology". Sky News. 17 July 2015. Retrieved 1 January 2016.
  16. ^ Roulstone, Ian; Norbury, John (25 July 2013). "How Math helped forecast Hurricane Sandy". Scientific American. Retrieved 9 August 2013.
  17. ^ "Moderate-strength Nor'easter may hit Sandy-devastated areas Wednesday | Category 6™". Archived from the original on 25 March 2017. Retrieved 1 May 2017.
  18. ^ Dee, D. P.; Uppala, S. M.; Simmons, A. J.; Berrisford, P.; Poli, P.; et al. (2011). "The ERA-Interim reanalysis: Configuration and performance of the data assimilation system". Quarterly Journal of the Royal Meteorological Society. 137 (656): 553–597. Bibcode:2011QJRMS.137..553D. doi:10.1002/qj.828. hdl:20.500.11824/1106.
  19. ^ Hersbach, H.; Bell, B.; Berrisford, P.; Hirahara, S.; Horányi, A.; Muñoz-Sabater, J.; et al. (2020). "The ERA5 global reanalysis". Quarterly Journal of the Royal Meteorological Society. 146 (730): 1999–2049. doi:10.1002/qj.3803.
  20. ^ "New ERA5 dataset provides weather and climate details back to 1979". 17 January 2019.
  21. ^ "Modelling and Prediction". ECMWF. 29 November 2013. Retrieved 2 January 2016.
  22. ^ Paul Douglas (18 April 2021). "Will a New GFS Weather Model Upgrade Close the Gap with The European Model?". AerisWeather. Retrieved 14 September 2021.
  23. ^ "Copernicus Atmosphere Monitoring Service". ECMWF. 11 November 2014. Retrieved 23 October 2019.
  24. ^ "Copernicus Climate Change Service". ECMWF. 11 November 2014. Retrieved 23 October 2019.
  25. ^ "MeteoWorld". 22 September 2015.
  26. ^ "Slovenia becomes ECMWF's 20th Member State". ECMWF. Archived from the original on 3 September 2013. Retrieved 8 December 2012.
  27. ^ Jeppesen, Joanne (5 January 2015). "Serbia becomes ECMWF's 21st Member State". ECMWF.
  28. ^ Jeppesen, Joanne (1 July 2016). "News". ECMWF.
  29. ^ "ECMWF welcomes Estonia as 23rd Member State". 1 December 2020.
  30. ^ "ECMWF Member States". ECMWF. 2017.
  31. ^ "ECMWF Co-operating States". ECMWF. 2017.
  32. ^ "ECMWF Co-operating Agreements". ECMWF. 2017.

Further reading

"ERA-15". Archived from the original on 11 August 2004.
"ERA-40". Archived from the original on 11 August 2004.