Frost dates · USDA zone 6a
Frost dates for Chicago, IL
Chicago, IL sees its last 32 °F night of spring around April 10 and its first of fall around November 5 — a 208-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Mar 29 | Nov 20 |
| Median — 1 year in 2 | Apr 10 | Nov 5 |
| 1 year in 10 | Apr 25 | Oct 24 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 208 days median, at least 187 in 9 years of 10, at least 229 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Apr 1 and first of Nov 15.
Chicago planting calendar, 2027
Every row runs from the median last frost (Apr 10) and median first frost (Nov 5) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Jan 16 | Mar 13 | Jul 1 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 10 | May 10 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 27 | Mar 27 | May 11 | 45 from sow |
| Genovese BasilGenovese | Mar 13 | Apr 24 | Jun 23 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Feb 13 | Apr 17 | Jul 1 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 30 | Apr 24 | Jul 28 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Feb 13 | Apr 17 | Jul 1 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Feb 13 | Apr 17 | Jul 6 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Feb 13 | Apr 17 | Jul 6 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 27 | Mar 27 | Jun 5 | 70 from sow |
| TomatilloToma Verde | Feb 27 | Apr 17 | Jun 26 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 27 | Apr 17 | Jul 1 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 27 | Apr 17 | Jul 6 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Chicago grow?
Each sauce, scheduled for a Chicago container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Chicago frost questions
When is the last frost in Chicago, IL?
The median last 32 °F freeze at CHICAGO NORTHERLY IS, IL is April 10: half of years see a later one. One year in ten, a freeze still comes after April 25; nine years in ten, it comes after March 29. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Chicago, IL?
The median first 32 °F freeze of fall is November 5. One year in ten it arrives before October 24; nine years in ten, before November 20.
How long is the growing season in Chicago, IL?
208 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 187 days; one year in ten, at least 229 days.
What growing zone is Chicago, IL?
USDA hardiness zone 6a, per the 2023 USDA Plant Hardiness Zone Map for ZIP 60608. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Chicago, IL?
Start Roma VF (determinate paste) seeds indoors around Feb 27 and transplant around Apr 17, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 25. First ripe fruit lands around Jul 1.
When should I plant peppers in Chicago, IL?
Sow jalapeño indoors on a heat mat around Feb 13; transplant no earlier than Apr 17, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 1.
Nearby in Illinois
- Cicerolast frost Apr 11
- Berwynlast frost Apr 11
- Oak Parklast frost Apr 11
- Oak Lawnlast frost Apr 10
- Elmhurstlast frost Apr 16
- Skokielast frost Apr 26
All Illinois frost dates → · How frost-date math drives a sowing calendar →