Frost dates for Flora, IL
At Flora, the median last spring frost (32°F) is Apr 9 and the median first fall frost is Oct 24, for a typical growing season of 198 days. For a 90% chance that the last frost has passed, wait until Apr 23. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 9Last spring frost (median)50% chance of 32°F after this date
- Apr 23Safer planting date10% chance of 32°F after this date
- Oct 24First fall frost (median)50% chance of 32°F by this date
- 198 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 8 | Apr 21 | May 6 |
| 32°F | Mar 29 | Apr 9 | Apr 23 |
| 28°F | Mar 14 | Mar 31 | Apr 14 |
| 24°F | Mar 1 | Mar 20 | Apr 4 |
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 1 | Oct 15 | Oct 26 |
| 32°F | Oct 11 | Oct 24 | Nov 6 |
| 28°F | Oct 22 | Nov 3 | Nov 19 |
| 24°F | Nov 1 | Nov 15 | Dec 1 |
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 | 154 days | 175 days | 194 days |
| 32°F | 177 days | 198 days | 217 days |
| 28°F | 198 days | 218 days | 240 days |
| 24°F | 219 days | 240 days | 264 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 |
|---|---|---|---|
| 62839 | 6b | -5 to 0°F | 2 km |
| 62878 | 6b | -5 to 0°F | 12 km |
| 62824 | 6b | -5 to 0°F | 12 km |
| 62879 | 6b | -5 to 0°F | 14 km |
| 62850 | 6b | -5 to 0°F | 23 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 USC00113106, at 38.6781, -88.4797, elevation 147 m (481 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 109.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Flora 5 NW (9 km)
- Olney 2s (35 km)
- Fairfield Radio Wfiw (36 km)
- Salem (41 km)
- Newton 6 SSE (41 km)
- Newton (43 km)
- Iuka 12 SW (47 km)
- Mount Vernon 3 NE (49 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.