In Minnesota, an "ice in" date is when a lake is frozen over with a continuous and immobile ice cover for the first time that season. This date is determined by observers and is not based on a specific thickness, but rather on the first full, unbroken freeze that lasts more than a day.

View DNR data here - you can select a year and a specific lake: https://www.dnr.state.mn.us/ice_in/index.html?year=2025#map

An “ice out” is the day a lake is considered free of ice and navigable, which can have different definitions depending on the lake. Typically, it signifies the lake is either completely ice-free, has enough open water to navigate from point A to point B, or is at least 90% clear of ice.

View DNR data here - you can select a year and a specific lake: https://www.dnr.state.mn.us/ice_out/index.html

Neither the DNR nor the SRCLA measures ice thickness on Minnesota lakes. Your safety is your responsibility. Check ice thickness as you go.  

Ice is never 100% safe!

Learn more at https://www.dnr.state.mn.us/safety/ice/index.html