When is the last frost in Chicago, IL?

The average (50% probability) last spring frost in Chicago is April 16, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until May 1.

When is the first frost in Chicago?

The average first fall frost in Chicago is October 28, with a growing season of about 193 days.

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Chicago, Illinois frost dates

Average last spring frost: April 16. Average first fall frost: October 28. That gives a growing season of about 193 days. For frost-tender plants, a safer planting date is May 1, after which a freeze happens in only 1 year in 10.

Last frost (50%)

Apr 16

1-in-10 risk after May 1

First frost (50%)

Oct 28

1-in-10 risk before Oct 15

Growing season

193 days

median frost-free days

Hard freeze (28°F)

Apr 5

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	April 3	November 11
70%	April 11	November 3
50%	April 16	October 28
30%	April 22	October 24
10%	May 1	October 15

Read the spring column like this: there is a 10% chance of a 32°F freeze after May 1. These are NOAA probabilities for the Chicago Ohare International Airport weather station (USW00094846, elevation 201 m), 1991–2020.

Chicago vegetable planting calendar

Dates count from the 50% last-frost date (April 16). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (May 1) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Mar 26	Apr 23 (usually sown directly in the garden)
Broccoli	Feb 5	Mar 19
Brussels sprouts	Feb 5	Mar 19
Cabbage	Jan 29	Mar 12
Cauliflower	Feb 19	Apr 2
Sweet corn	Mar 19	Apr 16 (usually sown directly in the garden)
Cucumbers	Apr 2	Apr 23
Kale	Jan 29	Mar 12
Leeks	Jan 1	Mar 12
Lettuce	Feb 26	Apr 2
Melons	Apr 9	Apr 30
Onions	Dec 25	Mar 5 (from seed; sets and transplants go out at the same time)
Peas	Feb 19	Mar 19 (usually sown directly in the garden)
Peppers	Mar 5	Apr 30
Squash	Apr 9	Apr 30
Tomatoes	Feb 19	Apr 16

Offsets from Oregon State University Extension's seed-starting table. "Plant out" means transplant, or sow directly for crops usually grown from seed.

Fall frost and season extension

The first fall freeze usually arrives around October 28. There's a 1-in-10 chance it comes before October 15. Harvest tender crops such as basil, tomatoes, peppers and squash before then, or cover them on cold nights. Cool-season crops like kale, cabbage and Brussels sprouts handle light frost, and often taste sweeter after it. A hard freeze (28°F) typically comes around November 7.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Milwaukee, WI	Apr 19	Oct 29	~107 km
Madison, WI	May 1	Oct 10	~172 km
Peoria, IL	Apr 16	Oct 23	~206 km
Grand Rapids, MI	Apr 29	Oct 20	~221 km
Fort Wayne, IN	Apr 24	Oct 21	~252 km
Green Bay, WI	Apr 30	Oct 9	~278 km

More: all Illinois frost dates