MPR’s Dan Kraker investigates the warming waters of Lake Superior. In late August 2016, the average surface water temperature for the entire lake hit 68 and a half degrees (the second highest ever recorded). In Lake Superior, researchers at the University of Minnesota Duluth have found that summer surface water temperatures have increased by 5 degrees over the past 30 years.

Researchers believe there is strong connection between the amount of ice on the lake the previous winter, and how warm the lake gets the following summer.