Frost dates for Hermiston 2 NW, OR
At Hermiston 2 NW, the median last spring frost (32°F) is Apr 27 and the median first fall frost is Oct 7, for a typical growing season of 163 days. For a 90% chance that the last frost has passed, wait until May 11. Nearby ZIP codes are in USDA hardiness zone 7b.
- Apr 27Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 7First fall frost (median)50% chance of 32°F by this date
- 163 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 29 | May 11 | May 26 |
| 32°F | Apr 11 | Apr 27 | May 11 |
| 28°F | Mar 25 | Apr 10 | Apr 29 |
| 24°F | Mar 3 | Mar 21 | Apr 8 |
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 11 | Sep 26 | Oct 9 |
| 32°F | Sep 25 | Oct 7 | Oct 21 |
| 28°F | Oct 5 | Oct 20 | Nov 2 |
| 24°F | Oct 16 | Nov 1 | Nov 19 |
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 | 113 days | 136 days | 155 days |
| 32°F | 143 days | 163 days | 183 days |
| 28°F | 172 days | 193 days | 215 days |
| 24°F | 200 days | 224 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 |
|---|---|---|---|
| 97838 | 7b | 5 to 10°F | 2 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 USC00353818, at 45.8619, -119.3120, elevation 140 m (460 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 122.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Hermiston Muni Airport (6 km)
- McNary Dam #2 (8 km)
- Boardman (30 km)
- Pendleton (40 km)
- Pendleton WFO (40 km)
- Pendleton Dwtn (45 km)
- Pendleton Branch Exp. Station (55 km)
- Pilot Rock 1 SE (57 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.