Frost dates for Wallowa, OR
At Wallowa, the median last spring frost (32°F) is Jun 7 and the median first fall frost is Sep 9, for a typical growing season of 91 days. For a 90% chance that the last frost has passed, wait until Jul 7. Nearby ZIP codes are in USDA hardiness zone 6b.
- Jun 7Last spring frost (median)50% chance of 32°F after this date
- Jul 7Safer planting date10% chance of 32°F after this date
- Sep 9First fall frost (median)50% chance of 32°F by this date
- 91 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 |
|---|---|---|---|
| 32°F | May 14 | Jun 7 | Jul 7 |
| 28°F | Apr 29 | May 11 | May 29 |
| 24°F | Apr 11 | Apr 28 | May 11 |
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 |
|---|---|---|---|
| 32°F | Aug 24 | Sep 9 | Sep 27 |
| 28°F | Sep 5 | Sep 24 | Oct 8 |
| 24°F | Sep 19 | Oct 5 | Oct 21 |
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 | 30 days | 53 days | 81 days |
| 32°F | 58 days | 91 days | 120 days |
| 28°F | 108 days | 133 days | 154 days |
| 24°F | 140 days | 161 days | 189 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 |
|---|---|---|---|
| 97885 | 6b | -5 to 0°F | 9 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 USC00358997, at 45.5722, -117.5314, elevation 891 m (2,923 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 171.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Elgin (31 km)
- Enterprise 20 NNE (33 km)
- Joseph (34 km)
- Union (49 km)
- La Grande (51 km)
- Meacham (70 km)
- Milton Freewater (80 km)
- Baker City Muni Airport (84 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.