Frost dates for Mattoon, IL
At Mattoon, the median last spring frost (32°F) is Apr 11 and the median first fall frost is Oct 29, for a typical growing season of 199 days. For a 90% chance that the last frost has passed, wait until Apr 28. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- Apr 11Last spring frost (median)50% chance of 32°F after this date
- Apr 28Safer planting date10% chance of 32°F after this date
- Oct 29First fall frost (median)50% chance of 32°F by this date
- 199 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 9 | Apr 23 | May 9 |
| 32°F | Mar 31 | Apr 11 | Apr 28 |
| 28°F | Mar 15 | Apr 2 | Apr 17 |
| 24°F | Mar 5 | Mar 22 | Apr 6 |
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 2 | Oct 19 | Oct 30 |
| 32°F | Oct 15 | Oct 29 | Nov 9 |
| 28°F | Oct 28 | Nov 7 | Nov 21 |
| 24°F | Nov 4 | 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 | 156 days | 175 days | 195 days |
| 32°F | 177 days | 199 days | 217 days |
| 28°F | 200 days | 219 days | 239 days |
| 24°F | 220 days | 239 days | 262 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 |
|---|---|---|---|
| 61938 | 6a | -10 to -5°F | 2 km |
| 61931 | 6a | -10 to -5°F | 13 km |
| 62469 | 6b | -5 to 0°F | 14 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 USC00115430, at 39.4725, -88.3544, elevation 214 m (701 ft).
- Data quality: Representative (10+ years), 11 years of freeze data.
- Average days per year at or below 32°F: 108.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mattoon Coles Co Airport (6 km)
- Charleston (16 km)
- Neoga 4nw (18 km)
- Windsor (21 km)
- Sullivan 3s (24 km)
- Tuscola (36 km)
- Shelbyville Dam (37 km)
- Casey (38 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.