Adjusted and Homogenized Canadian Climate Data (AHCCD)

This web site provides adjusted and homogenized climate data for many climatological stations in Canada. These data were created for use in climate research including climate change studies. They incorporate a number of adjustments applied to the original station data to address shifts due to changes in instruments and in observing procedures. Sometimes the observations from several stations were joined to generate a long time series.

Users are strongly cautioned to determine the data suitability for their application. They should also be aware that ongoing research on adjustment techniques may result in future revisions of the datasets. The datasets are updated annually with the most recent data.

The adjusted and homogenized data are provided for four climate elements: Surface air temperature, Precipitation, Surface pressure, and Surface wind speed.

References

Mekis, É. and L.A. Vincent, 2011: An overview of the second generation adjusted daily precipitation dataset for trend analysis in Canada. Atmosphere-Ocean, 49(2), 163-177.

Vincent, L. A., M. M. Hartwell, and X. L. Wang, 2020: A third generation of homogenized temperature for trend analysis and monitoring changes in Canada’s climate. Atmosphere-Ocean., 58:3, 173-191, doi:10.1080/07055900.2020.1765728.

Wan, H., X. L. Wang, V. R. Swail, 2010: Homogenization and trend analysis of Canadian near-surface wind speeds. Journal of Climate, 23, 1209-1225.

Wan, H., X. L. Wang, V. R. Swail, 2007: A quality assurance system for Canadian hourly pressure data. J. Appl. Meteor. Climatol., 46, 1804-1817.

Data and Resources

Additional Info

Field Value
Last Updated April 17, 2026, 20:10 (UTC)
Created April 17, 2026, 20:10 (UTC)
contact_email dccah-ahccd@ec.gc.ca
contact_person {"en": "Government of Canada; Environment and Climate Change Canada,1-800-668-6767,ec.enviroinfo.ec@canada.ca", "fr": "Gouvernement du Canada; Environnement et Changement climatique Canada,ec.enviroinfo.ec@canada.ca"}
criticality_level []
data_dictionary ["climatology_meterology_atmosphere"]
geographic_scope []
open_canada_collection fgp
open_canada_date_published 2000-01-01 00:00:00
open_canada_keywords {"en": ["surface air temperature; precipitation; surface pressure; surface wind speed", "Weather and Climate", "Climate", "Climate change", "Provide Climate Information Products and Services", "Expand Scientific Knowledge for Climate Monitoring and Prediction", "National (CA)", "Science and Technology Branch", "Atmospheric Science and Technology", "Unclassified"], "fr": ["température de l'air de surface; précipitation pression de surface; vitesse du vent de surface", "Temps et climat", "Climat", "Changement climatique", "Fournir des services et des produits d'information sur le climat", "Approfondir les connaissances scientifiques et formuler de nouvelles méthodes de recherche le climat et le changement climatique", "National (CA)", "Direction générale des sciences et de la technologie", "Sciences et technologie atmosphériques", "Non Classifié"]}
open_canada_subject ["nature_and_environment", "science_and_technology"]
sensitivity_level unrestricted
title_fr Données Climatiques Canadiennes Ajustées et Homogénéisées (DCCAH)
update_frequency as_needed