Frost dates · USDA zone 6a
Frost dates for Oak Park, IL
Oak Park, IL sees its last 32 °F night of spring around April 11 and its first of fall around October 31 — a 201-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 30 | Nov 14 |
| Median — 1 year in 2 | Apr 11 | Oct 31 |
| 1 year in 10 | Apr 27 | Oct 20 |
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: 201 days median, at least 181 in 9 years of 10, at least 222 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 11.
Oak Park planting calendar, 2027
Every row runs from the median last frost (Apr 11) and median first frost (Oct 31) 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 17 | Mar 14 | Jul 2 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 11 | May 11 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 28 | Mar 28 | May 12 | 45 from sow |
| Genovese BasilGenovese | Mar 14 | Apr 25 | Jun 24 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Feb 14 | Apr 18 | Jul 2 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 31 | Apr 25 | Jul 29 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Feb 14 | Apr 18 | Jul 2 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Feb 14 | Apr 18 | Jul 7 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Feb 14 | Apr 18 | Jul 7 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 28 | Mar 28 | Jun 6 | 70 from sow |
| TomatilloToma Verde | Feb 28 | Apr 18 | Jun 27 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 28 | Apr 18 | Jul 2 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 28 | Apr 18 | Jul 7 | 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 Oak Park grow?
Each sauce, scheduled for a Oak Park container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Oak Park frost questions
When is the last frost in Oak Park, IL?
The median last 32 °F freeze at CHICAGO MIDWAY AP, IL is April 11: half of years see a later one. One year in ten, a freeze still comes after April 27; nine years in ten, it comes after March 30. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Oak Park, IL?
The median first 32 °F freeze of fall is October 31. One year in ten it arrives before October 20; nine years in ten, before November 14.
How long is the growing season in Oak Park, IL?
201 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 181 days; one year in ten, at least 222 days.
What growing zone is Oak Park, IL?
USDA hardiness zone 6a, per the 2023 USDA Plant Hardiness Zone Map for ZIP 60302. 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 Oak Park, IL?
Start Roma VF (determinate paste) seeds indoors around Feb 28 and transplant around Apr 18, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 27. First ripe fruit lands around Jul 2.
When should I plant peppers in Oak Park, IL?
Sow jalapeño indoors on a heat mat around Feb 14; transplant no earlier than Apr 18, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 2.
Nearby in Illinois
- Berwynlast frost Apr 11
- Cicerolast frost Apr 11
- Chicagolast frost Apr 10
- Elmhurstlast frost Apr 16
- Skokielast frost Apr 26
- Lombardlast frost Apr 28
All Illinois frost dates → · How frost-date math drives a sowing calendar →