The brisk air is a reminder that our local lakes will soon freeze, but predicting when is anyone’s guess. There is a complex interplay of many forces that uniquely influences each lake’s ice-on date. (Learn more about the Mendota Freeze Contest and make your guess for when Lake Mendota will freeze.)
Freezing air temperatures are obviously the driving force behind lake ice formation. Yet water has a high specific heat capacity. This means it takes a lot of energy to change the temperature of water compared to other materials. Therefore, air temperatures from much earlier in the season can impact timing of ice formation. A cool September, for instance, can set the stage for an earlier freeze.
