Simpson, IL 62943 Frost Dates
When can you plant in Simpson, IL?
Typically, the last spring freeze lands around 04/14, roughly 229 days out. The first fall frost typically arrives around 10/21, about 189 frost-free days later.
Simpson sits in USDA Zone 7a (0 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 8 weeks of growing season left in Simpson before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/14 is the middle of 30 years of NOAA records, not a promise. Plant by 03/28 and you're betting against frost in roughly 9 years out of 10. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Simpson compares
Simpson's growing season runs about 189 days, ranking 21,773 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 660 of 1,548.
Learn more
zone vs. frost date covers why Zone 7a and Simpson's frost date answer different questions. the frost range covers how to read the range around Simpson's dates instead of trusting one.