Annual Climate Trends and Impacts Summary for the Great Lakes Basin

A product of the Great Lakes Water Quality Agreement Annex 9

Coordinated by a partnership between climate services organizations in the U.S. and Canada, this product provides a synthesis report summarizing the previous years’ climate trends, events, new research, assessments, and related activities in the Great Lakes Region. This product is a contribution to the U.S.-Canada Great Lakes Water Quality Agreement, through Annex 9 on Climate Change Impacts, and to the national climate assessment processes in the U.S. and Canada. It should be cited as: Environment and Climate Change Canada and the U.S. National Oceanic and Atmospheric Administration. 2019 Annual Climate Trends and Impacts Summary for the Great Lakes Basin. 2020.

2019 Document

Documents also available at

During the 2019 reporting period, several notable events and trends were observed across the Great Lakes basin, including extreme cold from a polar vortex event and a period of extreme summer heat, which both set temperature records. The basin had a wet spring with impacts on water levels and  agriculture. Water levels in the five Great Lakes continued to be very high, with Lake Erie and Lake Ontario reaching their highest monthly mean water level on record. Locations around the basin experienced coastal flooding and erosion due to high water levels through summer and fall. At 80.9% areal coverage, Great Lakes maximum ice cover for the year was 25% above the long-term average.


Contributing Partners

Environment and Climate Change Canada
Great Lakes Environmental Research Laboratory
Great Lakes Integrated Sciences and Assessments
Great Lakes Water Quality Agreement
Midwestern Regional Climate Center
National Oceanic and Atmospheric Administration
Northeast Regional Climate Center


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