Frost dates for Hillsboro, OH
At Hillsboro, the median last spring frost (32°F) is Apr 24 and the median first fall frost is Oct 20, for a typical growing season of 178 days. For a 90% chance that the last frost has passed, wait until May 11. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 24Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 20First fall frost (median)50% chance of 32°F by this date
- 178 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 21 | May 4 | May 20 |
| 32°F | Apr 10 | Apr 24 | May 11 |
| 28°F | Mar 31 | Apr 12 | Apr 29 |
| 24°F | Mar 18 | Apr 2 | Apr 17 |
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 20 |
| 32°F | Oct 6 | Oct 20 | Nov 1 |
| 28°F | Oct 17 | Nov 1 | Nov 13 |
| 24°F | Oct 31 | Nov 10 | 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 | 137 days | 157 days | 175 days |
| 32°F | 157 days | 178 days | 196 days |
| 28°F | 180 days | 201 days | 221 days |
| 24°F | 203 days | 221 days | 245 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 |
|---|---|---|---|
| 45133 | 6b | -5 to 0°F | 9 km |
| 45132 | 6b | -5 to 0°F | 12 km |
| 45159 | 6b | -5 to 0°F | 14 km |
| 45135 | 6b | -5 to 0°F | 14 km |
| 45142 | 6b | -5 to 0°F | 17 km |
| 45624 | 6b | -5 to 0°F | 23 km |
| 45155 | 6b | -5 to 0°F | 25 km |
| 45172 | 6b | -5 to 0°F | 26 km |
| 45118 | 6b | -5 to 0°F | 27 km |
| 45679 | 6b | -5 to 0°F | 29 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 USC00333758, at 39.2333, -83.6092, elevation 290 m (953 ft).
- Data quality: Standard (24+ years of data), 28 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
- Cincinnati (28 km)
- WFO Wilmington (28 km)
- Wilmington 3 N (34 km)
- Washington Court House (37 km)
- Xenia 6 SSE (49 km)
- Ripley Exp. Farm (52 km)
- Chillicothe Mound City (54 km)
- Waverly (56 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.