Adjusted and Homogenized Canadian Climate Data (AHCCD)

Adjusted and Homogenized Canadian Climate Data (AHCCD) is an open dataset from Environment and Climate Change Canada with 22 files (HTML, WFS, WMS); catalogue record updated 2026-08-04. On CanQuery you can follow the original downloads. Files are available in English and French.

The AHCCD collection includes two types of climate datasets: homogenized and adjusted. The homogenized datasets include monthly or daily surface air temperature, precipitation, and wind speed data for hundreds of climatological locations across Canada. These datasets incorporate a homogenization process, which typically uses statistical methods to detect and remove discontinuities in observed climate records caused by non-climatic influences, such as changes in measurement instruments or monitoring station relocations. In some cases, non-statistical adjustment methods are also applied to correct measured values for known biases caused by instruments or observation techniques (for example, under-catch by certain rain gauges or wind effects). Sometimes, data from multiple nearest stations are combined to extend the length of the record. Together, these methods produce consistent and more reliable Canadian homogenized station data series suitable for detecting and analyzing climate trends and variability. The adjusted datasets are available for precipitation variables only (i.e., rainfall, snowfall, and total precipitation). These datasets do not undergo a homogenization process;…

Publisher

Environment and Climate Change Canada

Resources

22

Catalogue metadata updated

2026-08-04