Plum City, WI 54721 Frost Dates
54721, near Plum City, WI: the frost window
Typically, the last spring freeze lands around 05/01, roughly 246 days out. Fall's first freeze usually shows up around 10/10, roughly 162 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Plum City in Zone 4b (-25 to -20°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
Plum City's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/01 isn't a guarantee
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/15 and only about 1 year in 10 sees frost after that.
Plum City against the rest of the dataset
Plum City's growing season runs about 162 days, ranking 31,833 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 283 of 860.
Learn more
Two guides worth reading on 54721: the frost range, on how to read the range around Plum City's dates instead of trusting one, and local microclimates, on what one yard in Plum City can differ from the 54721 normal.