Mattoon, IL 61938 Frost Dates
When can you plant in Mattoon, IL?
Typically, the last spring freeze lands around 04/11, roughly 226 days out. The first fall frost typically arrives around 10/29, about 199 frost-free days later.
Mattoon sits in USDA Zone 6a (-10 to -5°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.
What to do before the first frost
About 9 weeks of growing season left in Mattoon before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/11 isn't a guarantee
04/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/31 and you're betting against frost in roughly 9 years out of 10. 04/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mattoon compares
At roughly 199 frost-free days, Mattoon places 18,046 of 40,283 ZIP codes in this dataset. Within IL, it ranks 287 of 1,548.
Learn more
the frost range covers how to read the range around Mattoon's dates instead of trusting one. local microclimates covers what one yard in Mattoon can differ from the 61938 normal.