We got data from the Minnesota Department of Natural Resources showing ice-out dates for 10 of the state's biggest and/or most popular lakes and created these line charts. The points on the charts represent the day of the year (number of days past January 1st). The fact that February doesn't always have the same number of days makes this approach a little problematic, but it's the best way to show the trend that lakes are losing their ice earlier than in the past.