Frost dates for Joseph, OR
At Joseph, the median last spring frost (32°F) is May 24 and the median first fall frost is Oct 1, for a typical growing season of 126 days. For a 90% chance that the last frost has passed, wait until Jul 6. Nearby ZIP codes are in USDA hardiness zone 6a.
- May 24Last spring frost (median)50% chance of 32°F after this date
- Jul 6Safer planting date10% chance of 32°F after this date
- Oct 1First fall frost (median)50% chance of 32°F by this date
- 126 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 6 | May 24 | Jul 6 |
| 28°F | Apr 21 | May 4 | May 26 |
| 24°F | Apr 4 | Apr 21 | May 5 |
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 | Sep 10 | Oct 1 | Oct 15 |
| 28°F | Sep 29 | Oct 13 | Oct 30 |
| 24°F | Oct 9 | Oct 25 | Nov 9 |
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 | 52 days | 86 days | 119 days |
| 32°F | 82 days | 126 days | 152 days |
| 28°F | 133 days | 160 days | 182 days |
| 24°F | 165 days | 186 days | 210 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 |
|---|---|---|---|
| 97846 | 6a | -10 to -5°F | 12 km |
| 97857 | 6a | -10 to -5°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 USC00354329, at 45.3497, -117.2242, elevation 1275 m (4,184 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 186.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wallowa (34 km)
- Enterprise 20 NNE (40 km)
- Union (53 km)
- Halfway (53 km)
- Elgin (60 km)
- Richland (65 km)
- La Grande (67 km)
- Baker City Muni Airport (73 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.