Chicago, IL Frost Dates & Growing Season

The two dates every Chicago garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 10
~50% chance of frost after
First fall frost
Nov 5
~50% chance of frost before
Growing season
209 days
frost-free stretch
USDA zone
6a
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Mar 29 Apr 10 Apr 25
First fall frost Nov 20 Nov 5 Oct 24
Hard freeze (28°F), median last Apr 1 · first Nov 15

Computed from NOAA 1991–2020 climate normals at the Chicago Northerly Is station (3 km from central Chicago). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Chicago

Computed from Chicago's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 13 – Feb 27 Apr 17 – Apr 24
🫑 Peppers Jan 30 – Feb 13 Apr 24 – May 1
🥬 Lettuce Feb 27 – Mar 13 Mar 13 – Mar 27 Mar 13 – Apr 10
🫛 Peas Feb 27 – Mar 13
🥕 Carrots Mar 20 – Apr 10
🥦 Broccoli Feb 20 – Mar 6 Mar 20 – Apr 3
🥬 Kale Feb 27 – Mar 13 Mar 13 – Mar 27 Mar 13 – Mar 27
🥒 Cucumbers Mar 13 – Mar 20 Apr 17 – Apr 24 Apr 17 – Apr 24
🥒 Zucchini Mar 13 – Mar 20 Apr 17 – Apr 24 Apr 17 – Apr 24
🫘 Green Beans (Bush) Apr 17 – Apr 24
🌽 Sweet Corn Apr 17 – Apr 24
🌿 Basil Feb 27 – Mar 13 Apr 17 – Apr 24 Apr 24 – May 1
🧄 Garlic Fall: Sep 24 – Oct 22

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Chicago's dates automatically after a lookup.

Reading the season in Chicago

With roughly 209 frost-free days, Chicago gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Nov 5 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Chicago, IL?

The average last spring frost in Chicago is around Apr 10, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Chicago, IL?

The average first fall frost in Chicago arrives around Nov 5. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Chicago?

About 209 frost-free days on average, from Apr 10 to Nov 5. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Chicago in?

USDA zone 6a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.