DeForest, WI 53571 Frost Dates
DeForest, WI: when does the frost end?
Around 05/04 is the usual last spring frost, about 249 days away. Fall's first freeze usually shows up around 10/06, roughly 154 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts DeForest in Zone 5a (-20 to -15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 6 weeks until DeForest's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
DeForest against the rest of the dataset
DeForest's growing season runs about 154 days, ranking 34,240 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 471 of 860.
Learn more
Before leaning on 53571's figures: the frost range explains how to read the range around DeForest's dates instead of trusting one, while local microclimates explains what one yard in DeForest can differ from the 53571 normal.