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WMO Climate Normals

The World Meteorological Organization (WMO) Climatological Standard Normals are a suite of data products that provide information about typical climate conditions for thousands of locations across the world. Countries (including the United States) produce climate normals that serve as a ruler to compare today’s weather and tomorrow’s forecast, and as a predictor of conditions in the near future. They are also used as a benchmark  to provide context to recent or current weather and climate conditions.

Upcoming Release (1991–2020)

The WMO will be taking data submissions for the 1991–2020 normals from member countries during late 2021 and 2022. The planned release date is August 1, 2023.  More information is available in the documentation and instructions folder and the About section of this page.

Climatological Standard Normals (1981–2010)

Climatological Reference Normals (1961–1990)

Project History

The Global Climatological Standard Normals are calculated for a uniform 30-year period, and consist of annual and monthly averages and statistics of temperature, precipitation, and other climatological variables. Since the early 1900s, countries have developed and provided Climatological Standard Normals on a tricennial basis (once every 30 years, e.g. 1901–1930, 1931–1960, 1961–1990). In 2015, the WMO, through the Seventeenth World Meteorological Congress (Cg-17), changed the definition of a Climatological Standard Normal to the most recent 30-year period finishing in a year ending with 0 (1981–2010, 1991–2020 etc) rather than to non-overlapping 30-year-periods (1931–1960, 1961–1990 etc).

NCEI, as host of the World Data Center for Meteorology, and in cooperation with the WMO, provides stewardship of these Global Normals including archive and access services.

Data Submission Guidance for the 1991–2020 WMO Normals

For the 1991–2020 Climatological Standard Normals, the WMO requests countries provide data that have been calculated and digitized in either EXCEL or ASCII *.csv format, following the calculation guidance provided in the WMO Guidelines on the Calculation of Climate Normals (WMO-No. 1203) as well as the Guidelines for the Submission of WMO Climatological Standard Normals (Annex 2). 

Countries are asked to submit the climatological normals for their country to the WMO Secretariat ( between October 1, 2021 and March 31, 2022. NCEI and the World Data Center for Meteorology will make the data available on this website by June 30, 2022.