Frost dates for Napoleon 1sw, OH
At Napoleon 1sw, the median last spring frost (32°F) is Apr 23 and the median first fall frost is Oct 24, for a typical growing season of 183 days. For a 90% chance that the last frost has passed, wait until May 9. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 23Last spring frost (median)50% chance of 32°F after this date
- May 9Safer planting date10% chance of 32°F after this date
- Oct 24First fall frost (median)50% chance of 32°F by this date
- 183 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 20 | May 4 | May 19 |
| 32°F | Apr 8 | Apr 23 | May 9 |
| 28°F | Mar 29 | Apr 11 | Apr 28 |
| 24°F | Mar 17 | Apr 1 | 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 30 | Oct 12 | Oct 25 |
| 32°F | Oct 10 | Oct 24 | Nov 6 |
| 28°F | Oct 23 | Nov 4 | Nov 17 |
| 24°F | Nov 3 | Nov 14 | 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 | 140 days | 160 days | 180 days |
| 32°F | 162 days | 183 days | 203 days |
| 28°F | 185 days | 206 days | 224 days |
| 24°F | 209 days | 227 days | 249 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 |
|---|---|---|---|
| 43555 | 6a | -10 to -5°F | 11 km |
| 43527 | 6a | -10 to -5°F | 15 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 USC00335667, at 41.3817, -84.1514, elevation 204 m (670 ft).
- Data quality: Estimated from nearby stations (2+ years), 6 years of freeze data.
- Average days per year at or below 32°F: 121.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Napoleon (3 km)
- Wauseon Water Plant (15 km)
- Defiance (23 km)
- Defiance Mem Airport (24 km)
- Bryan 2 SE (33 km)
- Hoytville 2 NE (37 km)
- Toledo Express Airport (37 km)
- Bowling Green Wastewater Plant (45 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.