Temperatures around Chicago are on the decline Saturday, but the water temperature in Lake Michigan is up, way up.
Triple-digit temperatures from this week's heatwave raised the water temperature of Lake Michigan up to 80 degrees.
The National Weather Service says that's "unprecedented" for this early in the summer season.
Meteorologists say monthly air temperatures have been above normal for nine consecutive months in Chicago. That translates to warm water temperatures across the lake. The heat wave drove up the lake temperature. The water temperature rose 10 degrees between Sunday and Friday.
The 80-degree water was recorded Friday by buoy on Lake Michigan, which is 43 nautical miles east-southeast of Milwaukee. The water depth of the buoy is 528 feet, and the temperature is measured about two feet below the water surface.