Frost dates for Washington Court House, OH
At Washington Court House, the median last spring frost (32°F) is Apr 23 and the median first fall frost is Oct 21, for a typical growing season of 181 days. For a 90% chance that the last frost has passed, wait until May 8. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- Apr 23Last spring frost (median)50% chance of 32°F after this date
- May 8Safer planting date10% chance of 32°F after this date
- Oct 21First fall frost (median)50% chance of 32°F by this date
- 181 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 19 | May 2 | May 19 |
| 32°F | Apr 10 | Apr 23 | May 8 |
| 28°F | Mar 29 | Apr 11 | Apr 25 |
| 24°F | Mar 17 | Apr 1 | Apr 14 |
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 27 | Oct 10 | Oct 22 |
| 32°F | Oct 8 | Oct 21 | Oct 31 |
| 28°F | Oct 20 | Nov 1 | Nov 14 |
| 24°F | Oct 31 | Nov 11 | Nov 28 |
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 | 160 days | 178 days |
| 32°F | 162 days | 181 days | 198 days |
| 28°F | 185 days | 203 days | 222 days |
| 24°F | 206 days | 226 days | 246 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 |
|---|---|---|---|
| 43160 | 6b | -5 to 0°F | 2 km |
| 43106 | 6b | -5 to 0°F | 12 km |
| 43145 | 6b | -5 to 0°F | 14 km |
| 43142 | 6b | -5 to 0°F | 15 km |
| 43128 | 6a | -10 to -5°F | 20 km |
| 45123 | 6b | -5 to 0°F | 21 km |
| 43143 | 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 USC00338794, at 39.5353, -83.4239, elevation 292 m (957 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 115.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wilmington 3 N (34 km)
- WFO Wilmington (36 km)
- Cincinnati (36 km)
- Hillsboro (37 km)
- Chillicothe Mound City (40 km)
- London Fish Hatchery (41 km)
- Circleville (41 km)
- Xenia 6 SSE (42 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.