2021 Annual Climate Trends and Impacts Summary for the Great Lakes Basin

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. 2021 Annual Climate Trends and Impacts Summary for the Great Lakes Basin. 2022.

2021 Document
English Version (PDF)
French Version (PDF)

Documents also available at binational.net















During the 2021 reporting period, several notable events and trends were observed across the Great Lakes basin, including warm air and water temperatures throughout the year, drought conditions, and flooding. Winter and spring drought contributed to wildfires and diminished the springtime rise in water levels. Water levels on the upper-Great Lakes began a return to near-average conditions, after years of above average water levels. For the southern basin, dry conditions gave way to above-average precipitation for the second half of the year. At 45.8% areal coverage, Great Lakes maximum ice cover in 2021 was below the long term average of 53.3%.


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
University of Illinois



Xie, F., Erler, A. R., Chandan, D., & Peltier, W. R. 2021. Great Lakes Basin Heat Waves: An analysis of their increasing probability of occurrence under global warming. Frontiers in Water, 3. https://doi.org/10.3389/frwa.2021.782265

Huziy, O., Teufel, B., Sushama, L., Yerubandi, R. 2021. Heavy Lake-Effect Snowfall Changes and Mechanisms for the Laurentian Great Lakes Region. Atmosphere, 12(12). https://doi.org/10.3390/atmos12121577

Toronto and Region Conservation Authority. 2021. Etobicoke Creek Watershed Plan. Retrieved March 24, 2022, from https://trca.ca/conservation/watershed-management/etobicoke-creek-watershed-plan/

Costa, D., Zhang, H., Levison, J. 2021. Impacts of climate change on groundwater in the Great Lakes Basin: A review. Journal of Great Lakes Research, 47(6). https://doi.org/10.1016/j.jglr.2021.10.011

Smith, D., S. Ramirez, D. Lix and C. Chu. 2021. Ontario Lakes and Climate Change Database: A guide to projected changes in the thermal conditions of Ontario’s inland lakes. Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry, Science and Research Branch, Climate Change Research Report CCRR-55. 50 p. + appendices.

Great Lakes Integrated Sciences and Assessments. 2021. Climate Model Report Cards. https://glisa.umich.edu/climate-model-report-cards/

Notaro, M., Y. Zhong, P. Xue, C. Peters-Lidard, C. Cruz, E. Kemp, and D. Kristovich et al. 2021. Cold Season Performance Of The NU-WRF Regional Climate Model In The Great Lakes Region. Journal Of Hydrometeorology. https://doi.org/10.1175/JHM-D-21-0025.1

Kiefer, M., Andresen, J., McCullough, D., Baule, W., Notaro, M. 2021. Extreme minimum temperatures in the Great Lakes region of the United States: A climatology with implications for insect mortality. International Journal of Climatology, 2021. https://doi.org/10.1002/joc.7434

Canada 1 Water. Canada 1 Water. https://www.canada1water.ca/

Wuebbles, D., J. Angel, K. Peterson, A. M. Lemke, 2021. An Assessment of the Impacts of Climate Change in Illinois. The Nature Conservancy. https://doi.org/10.13012/B2IDB-1260194_V1.  Available at: https://www.nature.org/content/dam/tnc/nature/en/documents/IL_Climate_Assessment_2021.pdf

American Society of Adaptation Professionals (ASAP). 2021. Climate Migration Workshop: Preparing Receiving Communities. https://adaptationprofessionals.org/resources/climate-migration-workshop-preparing-receiving-communities/

Galway, L., Esquega, E., Jones-Casey, K. 2021. “Land is everything, land is us”: Exploring the connections between climate change, land, and health in Fort William First Nation. Social Science & Medicine, 294. https://doi.org/10.1016/j.socscimed.2022.114700