The Actuaries Climate Index (ACI) has been updated with data through May 2025. The ACI provides objective measures of specific and aggregate changes in climate extremes and sea level across Canada and the U.S. and is based on an analysis of seasonal data from neutral, scientific sources for six index components collected since 1961.
The five-year ACI average increased from 1.37 to 1.43 for May 2025. The increase is due to shifts in nearly all metrics, including continuous dry days, precipitation, sea level and frequency of temperatures above the 90th percentile and below the 10th percentile.
With this update, the maps and graphs on the website have been revised, as well as the ACI data that is available for download. The Data Disclosure webpage summarizes important information about the data, and the Guided Tour webpage describes how to interpret the graphs and maps.
Thank you for your interest in the ACI, and for signing up for ACI updates from our email list. If you have any questions, please see the Contact Us webpage for the most appropriate contact.