Wilmington, IL 62078 Frost Dates
Frost dates for Wilmington, IL, ZIP 62078
The last spring frost here typically falls around 04/13, about 228 days from today. The first fall frost typically arrives around 10/22, about 190 frost-free days later.
Wilmington 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
Zone 6a around Wilmington has about 8 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 04/13 isn't a guarantee
04/13 is the middle of 30 years of NOAA records, not a promise. Plant by 03/30 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 Wilmington compares
Wilmington's growing season runs about 190 days, ranking 21,346 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 561 of 1,548.
Learn more
local microclimates explains what one yard in Wilmington can differ from the 62078 normal, and zone vs. frost date explains why Zone 6a and Wilmington's frost date answer different questions.