Cold overnight temperatures help Lake Mendota freeze, briefly
Ice on! 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.