About the Mendota Freeze Contest
Lake Mendota rings in the new year with a freeze! Temperatures below the freezing mark, combined with cold water, helped Lake Mendota officially freeze on January 1, 2026, as declared by the Wisconsin State Climatology Office. Lake Mendota, the largest lake in the Yahara Watershed, froze 12 days after December 20, which is the median ice-on date for the largest lake in the Yahara River Watershed. The latest date ice-on has been declared is January 30, 1932.
Thank you to the 1,936 weather watchers, lake lovers, and ice experts who submitted their Mendota Freeze Contest predictions. Those who guessed the correct date will be entered to win a gift card to Woodman’s Food Market or Faherty Brand at Hilldale — plus major bragging rights as a true local lake expert!
Freeze statistics for Lake Mendota
- For insight into the Wisconsin State Climatology Office, which declares the lakes frozen each year, read more about lake ice records from Wisconsin State Climatology Office
- The Wisconsin State Climatology Office makes the official determination as to whether the lake is frozen. The climatologists use the same guidelines they have used for decades. This allows for a continuity in data collection. Read more: Determining ice cover on Madison’s lakes.
- For statistics about determining the freeze date and the Madison ice record, see History of freezing and thawing of Lake Mendota and Madison lakes ice summary.
- To test your knowledge of our lakes in the winter, take the frozen lakes quiz.
About the Mendota Freeze Contest
On Saturday, November 15, 2025, Clean Lakes Alliance kicked off its 15th annual Mendota Freeze Contest. Calling on weather watchers and ice experts of all ages, the contest asks people to guess the official ice-on date for Lake Mendota. People who guess the correct date will be entered to win a gift card to an area business. (Only one guess per individual. Multiple entries will be automatically disqualified. Official rules and regulations can be found here.) All guesses must be submitted by 11:59 p.m. Central Time on Monday, December 15, 2025.
A look back at the 2024-25 season
Cold nighttime temperatures, combined with cold water and light winds, helped Lake Mendota officially freeze on December 25, 2024, as declared by the Wisconsin State Climatology Office. Two days later, on December 27th, Lake Mendota reopened as high temperatures climbed well into the 40s. The largest lake in the Yahara Watershed froze for the first time in the 2024-2025 winter season just five days after December 20th, which is the median ice-on date for Lake Mendota. The latest date ice-on has been declared is January 30th, and that took place in 1932.
The Wisconsin State Climatology Office requires ice to hold for a period of 24 hours before a lake can officially be declared frozen over. The December 25th freeze date is three weeks earlier than last winter’s January 15th freeze date. For statistics about determining the freeze date and the Madison ice record, see History of freezing and thawing of Lake Mendota and Madison lakes ice summary.
Contest Rules
Only one guess per individual. Multiple entries will be automatically disqualified. Official rules and regulations can be found here.
