Frost dates for Lisle-Morton Arboretum, IL
At Lisle-Morton Arboretum, the median last spring frost (32°F) is Apr 28 and the median first fall frost is Oct 16, for a typical growing season of 169 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- Apr 28Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 16First fall frost (median)50% chance of 32°F by this date
- 169 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 25 | May 9 | May 25 |
| 32°F | Apr 14 | Apr 28 | May 14 |
| 28°F | Apr 2 | Apr 16 | May 4 |
| 24°F | Mar 21 | Apr 5 | Apr 21 |
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 | Sep 22 | Oct 6 | Oct 18 |
| 32°F | Oct 1 | Oct 16 | Oct 29 |
| 28°F | Oct 12 | Oct 26 | Nov 8 |
| 24°F | Oct 25 | Nov 6 | Nov 23 |
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 | 129 days | 148 days | 167 days |
| 32°F | 148 days | 169 days | 188 days |
| 28°F | 169 days | 190 days | 210 days |
| 24°F | 193 days | 213 days | 235 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 |
|---|---|---|---|
| 60532 | 5b | -15 to -10°F | 3 km |
| 60515 | 6a | -10 to -5°F | 4 km |
| 60189 | 5b | -15 to -10°F | 5 km |
| 60137 | 5b | -15 to -10°F | 6 km |
| 60187 | 5b | -15 to -10°F | 7 km |
| 60516 | 5b | -15 to -10°F | 8 km |
| 60540 | 5b | -15 to -10°F | 8 km |
| 60148 | 6a | -10 to -5°F | 8 km |
| 60559 | 6a | -10 to -5°F | 9 km |
| 60517 | 6a | -10 to -5°F | 9 km |
| 60514 | 6a | -10 to -5°F | 9 km |
| 60555 | 5b | -15 to -10°F | 10 km |
| 60523 | 6a | -10 to -5°F | 10 km |
| 60565 | 6a | -10 to -5°F | 10 km |
| 60181 | 6a | -10 to -5°F | 11 km |
| 60139 | 5b | -15 to -10°F | 12 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 USC00115097, at 41.8128, -88.0728, elevation 207 m (680 ft).
- Data quality: Representative (10+ years), 13 years of freeze data.
- Average days per year at or below 32°F: 144.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wheaton 3 SE (0 km)
- West Chicago Dupage Airport (18 km)
- Aurora (20 km)
- Little Red School Hse (20 km)
- Romeoville WFO (23 km)
- Chicago Ohare Intl Airport (23 km)
- Streamwood (25 km)
- Chicago Midway Airport 3sw (26 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.