Madison lakes officially declared thawed and open

MADISON, Wis. (WMDX) – The ice on Lake Monona and Lake Mendota has officially thawed, as the state Climatology Office announced that less than 50% of the lakes were covered with ice on Wednesday. 

The unseasonably warm weather has led to the lakes thawing earlier than usual, with Monona being frozen for only 44 days, the shortest period on record. The previous record for shortest freeze-over was 49 days in the winter of 1997-98.

Lake Mendota was frozen for the second shortest period on record, also freezing for 44 days. The shortest freeze period on record was just 21 days in the winter of 2001-02.

Madison’s lakes have been staying frozen for shorter periods of time in recent years. On Lake Monona, the average freeze duration for its entire recorded history is 103 days. But in the past five years, it has been frozen for only 87 days. In Mendota, the five-year average freeze duration is 83 days. 

This year was the second earliest ice off date in Lake Mendota’s recorded history, missing the record for earliest thaw by just one day in 1998. This year is the third earliest ice off for Lake Monona, which thawed on February 27 in the winter of 1997-98 and February 26 in the winter of 2001-02.

“Many of us might enjoy warmer winter temperatures, but the long-term trend is not great for the health of our lakes or our economy,” said Clean Lakes Alliance Deputy Director and Chief Science Officer Paul Dearlove. “The early thaw will allow more sunlight to penetrate creating conditions more suitable for algae growth later in the season. Additionally, the shortened ice season means less anglers were able to come to town to fish our lakes and utilize our local businesses and restaurants.”

Many Madison-area events that usually take place on the frozen lakes had to be canceled this year due to the lack of safe ice. The Clean Lakes Alliance’s Frozen Assets Festival had to take most of their events off Lake Mendota. They were still able to hold the festival at The Edgewater. The UW Madison Memorial Union’s annual Winter Carnival also had to take many events off the lake, including the iconic Lady Liberty.