After temperatures in the 50s and 60s across Wisconsin over the last week, it's hard not to come down with a case of "spring fever," but don't let the warmth fool you into thinking it's safe to plant outdoors.

What You Need To Know

  • Average last freeze of the season does not typically occur until May

  • The southern part of the state usually sees its last freeze in early May

  • The northern parts of Wisconsin can see a freeze into late May

It's hard for green thumbs not to get excited about getting a jump-start on the growing season, but Wisconsin is no stranger to a frost or freeze late into the spring.

Average last spring freeze

When the temperature drops below freezing, damage can occur to plants and other vegetation that is sensitive to the cold. It's important to hold off on putting those fragile plants in the ground until our average last spring freeze has passed, marking the official start of the growing season.

In southern Wisconsin, our typical last freeze happens in early May but can occur as early as late April. Based on climate averages from 1981 to 2010, our last freeze in Milwaukee, Madison, and points between usually happens sometime between April 21 and May 10.

Farther north, colder air tends to hang on longer and sub-freezing temperatures can happen into late May. Our typical last spring freeze doesn't happen until around May 11 to May 31. This includes the cities of Green Bay, Wausau, and Rhinelander.

It could always be worse! Some parts of Michigan's Upper Peninsula won't escape those freezing mornings until sometime in early June. Try and resist the temptation to plant early, unless you're planting something hardy that can withstand some frosty mornings ahead!