Seymour, WI 54165 Frost Dates
54165, near Seymour, 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 10/11, roughly 160 days after the last spring frost.
Seymour 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
Seymour'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 04/19 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.
Seymour against the rest of the dataset
At roughly 160 frost-free days, Seymour places 32,318 of 40,283 ZIP codes in this dataset. Within WI, it ranks 344 of 860.
Learn more
Two guides worth reading on 54165: zone vs. frost date, on why Zone 5a and Seymour's frost date answer different questions, and the frost range, on how to read the range around Seymour's dates instead of trusting one.