Casco, WI 54205 Frost Dates
54205, near Casco, WI: the frost window
The last spring frost here typically falls around 05/01, about 246 days from today. Fall's first freeze usually shows up around 10/18, roughly 168 days after the last spring frost.
Zone 5b (-15 to -10°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 Casco, not a forecast for this year.
Stretching the season past the first frost
Casco's growing season runs out in roughly 7 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 04/16 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/17 and only about 1 year in 10 sees frost after that.
Casco against the rest of the dataset
At roughly 168 frost-free days, Casco places 29,755 of 40,283 ZIP codes in this dataset. Within WI, it ranks 148 of 860.
Learn more
Two guides worth reading on 54205: local microclimates, on what one yard in Casco can differ from the 54205 normal, and zone vs. frost date, on why Zone 5b and Casco's frost date answer different questions.