Clean Lakes Alliance contest: Guess when Lake Mendota will freeze, win Lands' End prize

This year’s Mendota Freeze Contest, says local nonprofit Clean Lakes Alliance, is anyone’s game. 

For the fourth year in a row, the organization is holding a free contest to guess the date when the Wisconsin State Climatology Office will declare Lake Mendota officially frozen. 

This year, an early cold snap that had Wisconsinites breaking out their down parkas in mid-November and thinking “polar vortex” made some contest hopefuls anticipate an early freeze for the city’s biggest lake. But an ongoing warm spell and still wide-open water on Lake Mendota got residents asking: how will recent weather affect lake ice?

Clean Lakes Alliance sought the help of Dr. John Magnuson, UW-Madison professor emeritus and an expert on climate change impacts on lakes, to explain.

According to Magnuson, this uncertainty is exactly what makes the Mendota Freeze Contest a good guessing game. In the last 30 years, Lake Mendota has frozen as early as Dec. 3 and as late as Jan. 20. 

“The [lake ice] record is so noisy and precise prediction is not yet within our grasp,” Magnuson said. “For example, when we had the cold snap early in the fall, everyone expected that the ice would freeze. But the cold snap went and the lake wasn’t frozen. And the people who guessed early have already lost.” 

Magnuson presented on lake ice trends for a recent Center for Limnology seminar at the University of Wisconsin-Madison. According to the center’s blog, “Things like weather patterns, climate cycles like the El Niño-Southern Oscillation, and even sunspots all play a role [in lake ice duration]. But... it’s still impossible to predict what, exactly, is running the show.” 

“Can we hazard a guess as to when Lake Mendota might freeze?” asked the center. The response: “Well, yes, but not much of one.” 

So what is Magnuson’s guess? 

“If I had to bet, I’d bet sometime in January,” says Magnuson. 

And beyond that 31-day window? Guess away. 

Visit to enter the Mendota Freeze Contest. This year’s grand prize winner will receive a $1,000 gift card to Lands’ End and the runner-up will win four tickets to the Walt Disney World theme parks in Orlando, Florida.

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