Chicago, IL 60605 Frost Dates
Frost dates for Chicago, IL, ZIP 60605
Typically, the last spring freeze lands around 04/10, roughly 225 days out. The first fall frost typically arrives around 11/05, about 208 frost-free days later.
Chicago sits in USDA Zone 6b (-5 to 0°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 6b around Chicago has about 10 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.
How much risk comes with planting early here
04/10 is the middle of 30 years of NOAA records, not a promise. Plant by 03/29 and you're betting against frost in roughly 9 years out of 10. 04/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Chicago compares
At roughly 208 frost-free days, Chicago places 15,459 of 40,283 ZIP codes in this dataset. Within IL, it ranks 55 of 1,548.
Learn more
local microclimates explains what one yard in Chicago can differ from the 60605 normal, and zone vs. frost date explains why Zone 6b and Chicago's frost date answer different questions.