Mattoon, WI 54150 Frost Dates
Mattoon, WI: when does the frost end?
The last spring frost here typically falls around 05/14, about 259 days from today. Fall's first freeze usually shows up around 09/30, roughly 139 days after the last spring frost.
Mattoon sits in USDA Zone 4b (-25 to -20°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
With roughly 5 weeks until Mattoon's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/14 isn't a guarantee
05/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/28 and only about 1 year in 10 sees frost after that.
Mattoon against the rest of the dataset
About 139 days separate Mattoon's last and first frost, putting it 37,269 of 40,283 ZIP codes nationally. Within WI, it ranks 735 of 860.
Learn more
Before leaning on 54150's figures: local microclimates explains what one yard in Mattoon can differ from the 54150 normal, while zone vs. frost date explains why Zone 4b and Mattoon's frost date answer different questions.