Wilmington, IL 60481 Frost Dates
When can you plant in Wilmington, IL?
Typically, the last spring freeze lands around 04/16, roughly 231 days out. The first fall frost typically arrives around 10/26, about 191 frost-free days later.
Wilmington sits in USDA Zone 5b (-15 to -10°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 Wilmington before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Wilmington's last frost
04/16 is the middle of 30 years of NOAA records, not a promise. Plant by 04/03 and you're betting against frost in roughly 9 years out of 10. 05/03 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Wilmington compares
About 191 days separate Wilmington's last and first frost, putting it 20,761 of 40,283 ZIP codes nationally. Within IL, it ranks 444 of 1,548.
Learn more
zone vs. frost date covers why Zone 5b and Wilmington's frost date answer different questions. the frost range covers how to read the range around Wilmington's dates instead of trusting one.