Illinois frost dates

Average last spring and first fall frost dates for Illinois’s largest cities, with each city’s USDA hardiness zone.

Reviewed October 2026

Among Illinois’s 20 largest cities, the average last spring frost ranges from Apr 10 in Chicago to Apr 30 in Waukegan. Elevation, distance from the coast and city heat all shift the date, so use your own ZIP code below for the closest match.

City	Average last spring frost	Average first fall frost	Frost-free days	Hardiness zone	Weather station used
Chicago	Apr 10	Nov 5	209	6a–6b	Chicago Northerly Is, IL, 4 mi
Aurora	Apr 19	Oct 23	187	5b	Aurora, IL, 2 mi
Naperville	Apr 28	Oct 16	171	5b–6a	Lisle-Morton Arboretum, IL, 6 mi
Joliet	Apr 19	Oct 25	189	5b–6a	Joliet Brandon Rd Dam, IL, 2 mi
Rockford	Apr 24	Oct 17	176	5b	Rockford Gtr Rockford Airport, IL, 5 mi
Elgin	Apr 26	Oct 18	175	5b	Elgin, IL, 3 mi
Springfield	Apr 15	Oct 22	190	6a	Springfield #2, IL, 2 mi
Peoria	Apr 16	Oct 23	190	5b–6a	Peoria Gtr Peoria Airport, IL, 7 mi
Champaign	Apr 15	Oct 24	192	6a	Champaign 3S, IL, 3 mi
Waukegan	Apr 30	Oct 19	172	6a	Waukegan, IL, 2 mi
Cicero	Apr 11	Oct 31	203	6a	Chicago Midway Airport, IL, 4 mi
Bloomington	Apr 25	Oct 16	174	6a	Normal 4Ne, IL, 5 mi
Schaumburg	Apr 30	Oct 13	166	5b–6a	Streamwood, IL, 5 mi
Evanston	Apr 26	Oct 21	178	6a	Chicago Botanic Garden, IL, 8 mi
Arlington Heights	Apr 19	Oct 26	190	5b–6a	Chicago Palwaukee Airport, IL, 4 mi
Bolingbrook	Apr 20	Oct 22	185	5b–6a	Romeoville Wfo, IL, 6 mi
Decatur	Apr 14	Oct 24	193	6a	Decatur Wtp, IL, 2 mi
Palatine	Apr 25	Oct 19	177	5b–6a	Barrington 3Sw, IL, 6 mi
Skokie	Apr 26	Oct 21	178	6a	Chicago Botanic Garden, IL, 8 mi
Des Plaines	Apr 16	Oct 28	195	6a	Chicago Ohare Intl Airport, IL, 3 mi

Frost dates are the dates after (spring) or before (fall) which the chance of a 32°F freeze is below 50%, from NOAA’s 1991–2020 U.S. Climate Normals for the weather station nearest each city’s center. Zones are from the 2023 USDA Plant Hardiness Zone Map for the ZIP codes around each city; a range means nearby ZIP codes differ. Cities are the 20 largest by Census Bureau 2024 population estimates.

An average is not a guarantee. There’s still about a 1 in 2 chance of frost after the average last spring date. Many gardeners wait an extra week or two before setting out tomatoes, peppers and basil, and keep covers handy.

Planting dates for Chicago

Timed from Chicago’s average last frost of Apr 10, using University of New Hampshire Extension’s planting guidance. For your exact dates, enter your ZIP code in the calendar below.

Crop	Start seeds indoors	Plant outside
Tomatoes	Feb 20 to Mar 6	Apr 17 to Apr 24
Peppers	Feb 13 to Feb 27	Apr 24
Lettuce	Feb 6 to Feb 13	Mar 13 to Mar 20
Broccoli	Jan 30 to Feb 13	Mar 13 to Mar 27
Cucumbers	Mar 20 to Mar 27	Apr 17 to Apr 24
Basil	Feb 27 to Mar 13	Apr 24

When to plant, for your garden

Your seed-starting and planting dates, timed from your last spring frost. Full calendar, 12 crops.

ZIP code

Last frost date

Enter your ZIP code to look up your average last frost date and hardiness zone, or type the date in yourself.

Frost dates: NOAA U.S. Climate Normals, 1991–2020. Hardiness zones: USDA Plant Hardiness Zone Map, 2023, ZIP code data from PRISM Group, Oregon State University, prism.oregonstate.edu, accessed Oct. 20, 2026.

More about frost dates

How to find your last frost date, and what your zone means · Full planting calendar · How to start seeds indoors

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