South Wilmington, IL 60474 Frost Dates
When can you plant in South Wilmington, IL?
Typically, the last spring freeze lands around 04/27, roughly 242 days out. The first fall frost typically arrives around 10/15, about 170 frost-free days later.
Zone 5b (-15 to -10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for South Wilmington, not a forecast for this year.
What to do before the first frost
About 7 weeks of growing season left in South Wilmington before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/27 isn't a guarantee
04/27 is the middle of 30 years of NOAA records, not a promise. Plant by 04/14 and you're betting against frost in roughly 9 years out of 10. 05/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How South Wilmington compares
South Wilmington's growing season runs about 170 days, ranking 29,161 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 1,406 of 1,548.
Learn more
zone vs. frost date covers why Zone 5b and South Wilmington's frost date answer different questions. the frost range covers how to read the range around South Wilmington's dates instead of trusting one.