Osceola, WI 54020 Frost Dates
54020, near Osceola, WI: the frost window
The last spring frost here typically falls around 05/04, about 249 days from today. Fall's first freeze usually shows up around 10/08, roughly 156 days after the last spring frost.
Zone 4b (-25 to -20°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Osceola, not a forecast for this year.
Stretching the season past the first frost
Osceola'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 05/04 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.
Osceola against the rest of the dataset
At roughly 156 frost-free days, Osceola places 33,627 of 40,283 ZIP codes in this dataset. Within WI, it ranks 420 of 860.
Learn more
Two guides worth reading on 54020: zone vs. frost date, on why Zone 4b and Osceola's frost date answer different questions, and the frost range, on how to read the range around Osceola's dates instead of trusting one.