Sun Prairie, WI 53590 Frost Dates
53590, near Sun Prairie, 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 160 days after the last spring frost.
Sun Prairie sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Sun Prairie'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.
The actual range around Sun Prairie's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/16 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
Sun Prairie against the rest of the dataset
About 160 days separate Sun Prairie's last and first frost, putting it 32,227 of 40,283 ZIP codes nationally. Within WI, it ranks 333 of 860.
Learn more
Two guides worth reading on 53590: local microclimates, on what one yard in Sun Prairie can differ from the 53590 normal, and zone vs. frost date, on why Zone 5a and Sun Prairie's frost date answer different questions.