Frost dates for Avon, IL
At Avon, the median last spring frost (32°F) is Apr 22 and the median first fall frost is Oct 19, for a typical growing season of 177 days. For a 90% chance that the last frost has passed, wait until May 8. Nearby ZIP codes are in USDA hardiness zone 5b.
- Apr 22Last spring frost (median)50% chance of 32°F after this date
- May 8Safer planting date10% chance of 32°F after this date
- Oct 19First fall frost (median)50% chance of 32°F by this date
- 177 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 17 | May 2 | May 16 |
| 32°F | Apr 7 | Apr 22 | May 8 |
| 28°F | Mar 26 | Apr 10 | Apr 28 |
| 24°F | Mar 12 | Mar 31 | Apr 15 |
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 24 | Oct 9 | Oct 21 |
| 32°F | Oct 5 | Oct 19 | Oct 29 |
| 28°F | Oct 14 | Oct 27 | Nov 10 |
| 24°F | Oct 26 | Nov 7 | Nov 24 |
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 | 140 days | 157 days | 175 days |
| 32°F | 158 days | 177 days | 195 days |
| 28°F | 177 days | 199 days | 219 days |
| 24°F | 200 days | 221 days | 243 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 |
|---|---|---|---|
| 61415 | 5b | -15 to -10°F | 3 km |
| 61474 | 5b | -15 to -10°F | 10 km |
| 61417 | 5b | -15 to -10°F | 15 km |
| 61410 | 5b | -15 to -10°F | 15 km |
| 61473 | 5b | -15 to -10°F | 18 km |
| 61544 | 5b | -15 to -10°F | 18 km |
| 61432 | 5b | -15 to -10°F | 25 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 USC00110356, at 40.6633, -90.4447, elevation 195 m (640 ft).
- Data quality: Estimated from nearby stations (2+ years), 8 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
- Prairie City 2s (8 km)
- Knoxville (30 km)
- Galesburg (32 km)
- Monmouth (35 km)
- Monmouth 4nw (38 km)
- La Harpe (45 km)
- Havana (51 km)
- Gladstone Dam 18 (54 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.