Cooler by the lake: Lake Superior water temps still frigid

Where do you go to beat the heat in a Minnesota summer? How about the world’s largest freshwater lake by surface area?

We all know it’s usually cooler by Lake Superior in summer. In fact, early summer can bring some of the biggest water to air temperature contrasts of the year. And that huge frigid pool of water has a major impact on local weather patterns by the lake.

Heatwave continues

One look at the temperature map and you can almost feel the heat. Red is the color of choice. I saw 97 degrees Tuesday in Madison, Appleton and Moorhead in western Minnesota.

Now look at the zone around the Great Lakes. You can see the soothing yellow hues with temperatures in the 70s.

If you get really close to the water, it’s 57 degrees at the bay of Grand Marais.

Cool, clear, water

Water temperatures on Lake Superior typically bottom out in March and peak in early September. The icy spring chill lingers well into early summer. Water temperatures on parts of the big lake still hovered in the 40s and 50s Tuesday.

The process of cooling the air near the lake is called air mass modification. As you can see on the maps above, the temperature difference between the hottest areas in Minnesota and the surface of Lake Superior Tuesday afternoon is more than 50 degrees.

That’s why temperatures near Lake Superior can change so quickly based on wind direction in summer. Any wind off the lake delivers much colder temperatures.