Frost dates for Dwight, IL
At Dwight, the median last spring frost (32°F) is Apr 27 and the median first fall frost is Oct 15, for a typical growing season of 170 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zone 5b.
- Apr 27Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 15First fall frost (median)50% chance of 32°F by this date
- 170 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 23 | May 7 | May 26 |
| 32°F | Apr 14 | Apr 27 | May 14 |
| 28°F | Apr 3 | Apr 17 | May 2 |
| 24°F | Mar 20 | 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 20 | Oct 3 | Oct 17 |
| 32°F | Sep 30 | Oct 15 | Oct 27 |
| 28°F | Oct 13 | Oct 25 | Nov 7 |
| 24°F | Oct 23 | Nov 4 | Nov 19 |
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 | 126 days | 149 days | 169 days |
| 32°F | 148 days | 170 days | 188 days |
| 28°F | 170 days | 192 days | 211 days |
| 24°F | 193 days | 214 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 |
|---|---|---|---|
| 60420 | 5b | -15 to -10°F | 2 km |
| 60424 | 5b | -15 to -10°F | 9 km |
| 60920 | 5b | -15 to -10°F | 12 km |
| 60437 | 5b | -15 to -10°F | 13 km |
| 60474 | 5b | -15 to -10°F | 14 km |
| 60961 | 5b | -15 to -10°F | 16 km |
| 60479 | 5b | -15 to -10°F | 17 km |
| 60934 | 5b | -15 to -10°F | 18 km |
| 60917 | 5b | -15 to -10°F | 19 km |
| 60919 | 5b | -15 to -10°F | 20 km |
| 60935 | 5b | -15 to -10°F | 21 km |
| 60969 | 5b | -15 to -10°F | 22 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 USC00112500, at 41.1072, -88.4111, elevation 191 m (628 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 140.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Morris 1 NW (29 km)
- Pontiac (32 km)
- Streator 3 SE (34 km)
- Channahon Dresden Isl Dam (34 km)
- Marseilles Lock (38 km)
- Piper City (43 km)
- Kankakee Metro Wastewater (44 km)
- Chenoa (48 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.