The dates of the freeze ("ice in") and thaw ("ice out") for nearly three dozen lakes in Wisconsin have been monitored for decades to more than 150 years.  From these dates, the total ice duration on the lakes for each season has been computed, representing the total number of days that I remained on the lakes. (Note: Some lakes, such as the Madison area lakes may have experienced several separate times in a season when ice covered the lake. The duration listed here reflects the total number of days of ice cover, and not necessarily the length of time elapsed between the dates of first ice in and last ice out.  Links to graphs of the lake ice duration for selected lakes over the course of several winter seasons appear in the tables below.  Some of these data were obtained from global lake and river ice phenology files provided to the National Snow and Ice Data Center (NSIDC) by a variety of researchers, to include John Magnuson and Dale Robertson.

Numbers on map correspond to list of lakes below: