Great Lakes Water Temperatures Remain High

By Samantha Cantie.

Lake Ontario broke a record this July for hottest surface water temperature ever recorded on the lake since 1995.

Lake Ontario isn’t alone. All five of the Great Lakes’ surface water temperatures are still above their 1995-2020 averages as of Aug. 21,  according to NOAA Great Lakes CoastWatch.

According to air temperature predictions made by NOAA Weather Service, above normal air temperatures during the rest of August and September could potentially translate to continued high surface temperatures in the Great Lakes for the rest of summer.

The most staggering representation of these increased temperatures comes from Lake Ontario, which reached 76.928 degrees Fahrenheit on July 10. That is 9.72 degrees above the average temperature for July 10 from 1995 to 2020 and constitutes the warmest surface water temperature ever recorded on Lake Ontario, according to NOAA CoastWatch data. The surface water temperature of Lake Ontario continues to remain above average, having hit 73.814 degrees Fahrenheit on Aug. 20.

These high water temperatures are mainly caused by persistent warm weather along with light winds.

“Climate change is clearly affecting the Great Lakes,” Andrea Vanderwoude, manager of the Great Lakes CoastWatch, said in an email. “This particular warming is consistent with the larger warming that is occurring.”