Frost dates for Napoleon, OH
At Napoleon, the median last spring frost (32°F) is Apr 24 and the median first fall frost is Oct 21, for a typical growing season of 179 days. For a 90% chance that the last frost has passed, wait until May 7. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 24Last spring frost (median)50% chance of 32°F after this date
- May 7Safer planting date10% chance of 32°F after this date
- Oct 21First fall frost (median)50% chance of 32°F by this date
- 179 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 2 | May 17 |
| 32°F | Apr 13 | Apr 24 | May 7 |
| 28°F | Mar 31 | Apr 14 | Apr 26 |
| 24°F | Mar 20 | Apr 4 | 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 9 | Oct 23 |
| 32°F | Oct 5 | Oct 21 | Nov 3 |
| 28°F | Oct 18 | Nov 1 | Nov 15 |
| 24°F | Oct 31 | Nov 11 | Nov 29 |
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 | 159 days | 176 days |
| 32°F | 161 days | 179 days | 197 days |
| 28°F | 183 days | 201 days | 219 days |
| 24°F | 202 days | 222 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 |
|---|---|---|---|
| 43545 | 6a | -10 to -5°F | 1 km |
| 43523 | 6a | -10 to -5°F | 11 km |
| 43535 | 6a | -10 to -5°F | 12 km |
| 43532 | 6a | -10 to -5°F | 14 km |
| 43510 | 6a | -10 to -5°F | 16 km |
| 43534 | 6a | -10 to -5°F | 16 km |
| 43524 | 6a | -10 to -5°F | 20 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 USC00335669, at 41.3939, -84.1144, elevation 208 m (682 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 134.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Napoleon 1sw (3 km)
- Wauseon Water Plant (14 km)
- Defiance (26 km)
- Defiance Mem Airport (27 km)
- Toledo Express Airport (34 km)
- Hoytville 2 NE (35 km)
- Bryan 2 SE (35 km)
- Bowling Green Wastewater Plant (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.