Frost dates for Chicago Ohare Intl Airport, IL
At Chicago Ohare Intl Airport, the median last spring frost (32°F) is Apr 16 and the median first fall frost is Oct 28, for a typical growing season of 193 days. For a 90% chance that the last frost has passed, wait until May 1. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- Apr 16Last spring frost (median)50% chance of 32°F after this date
- May 1Safer planting date10% chance of 32°F after this date
- Oct 28First fall frost (median)50% chance of 32°F by this date
- 193 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 15 | Apr 29 | May 13 |
| 32°F | Apr 3 | Apr 16 | May 1 |
| 28°F | Mar 21 | Apr 5 | Apr 19 |
| 24°F | Mar 7 | Mar 24 | Apr 8 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 3 | Oct 18 | Oct 30 |
| 32°F | Oct 15 | Oct 28 | Nov 11 |
| 28°F | Oct 27 | Nov 7 | Nov 22 |
| 24°F | Nov 3 | Nov 17 | Dec 2 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 151 days | 170 days | 189 days |
| 32°F | 173 days | 193 days | 213 days |
| 28°F | 198 days | 217 days | 238 days |
| 24°F | 217 days | 238 days | 260 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 60106 | 6a | -10 to -5°F | 4 km |
| 60018 | 6a | -10 to -5°F | 4 km |
| 60191 | 6a | -10 to -5°F | 5 km |
| 60007 | 6a | -10 to -5°F | 6 km |
| 60176 | 6a | -10 to -5°F | 7 km |
| 60016 | 6a | -10 to -5°F | 7 km |
| 60143 | 6a | -10 to -5°F | 8 km |
| 60131 | 6a | -10 to -5°F | 8 km |
| 60068 | 6a | -10 to -5°F | 8 km |
| 60005 | 6a | -10 to -5°F | 9 km |
| 60656 | 6a | -10 to -5°F | 9 km |
| 60164 | 6a | -10 to -5°F | 9 km |
| 60101 | 6a | -10 to -5°F | 9 km |
| 60631 | 6a | -10 to -5°F | 10 km |
| 60706 | 6a | -10 to -5°F | 10 km |
| 60157 | 5b | -15 to -10°F | 10 km |
| 60714 | 6a | -10 to -5°F | 11 km |
| 60126 | 6a | -10 to -5°F | 11 km |
| 60171 | 6a | -10 to -5°F | 11 km |
| 60165 | 6a | -10 to -5°F | 11 km |
| 60008 | 6a | -10 to -5°F | 11 km |
| 60160 | 6a | -10 to -5°F | 12 km |
| 60634 | 6a | -10 to -5°F | 12 km |
| 60163 | 6a | -10 to -5°F | 12 km |
| 60707 | 6a | -10 to -5°F | 13 km |
| 60104 | 6a | -10 to -5°F | 13 km |
| 60646 | 6a | -10 to -5°F | 14 km |
| 60162 | 6a | -10 to -5°F | 14 km |
| 60630 | 6a | -10 to -5°F | 15 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00094846, at 41.9950, -87.9336, elevation 201 m (658 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 121.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Chicago Palwaukee Airport (14 km)
- Chicago Botanic Garden (20 km)
- Streamwood (21 km)
- Barrington 3sw (23 km)
- Lisle-Morton Arboretum (23 km)
- Wheaton 3 SE (23 km)
- West Chicago Dupage Airport (27 km)
- Chicago Midway Airport (28 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.