Frost dates for Pilot Rock 1 SE, OR
At Pilot Rock 1 SE, the median last spring frost (32°F) is May 7 and the median first fall frost is Oct 4, for a typical growing season of 147 days. For a 90% chance that the last frost has passed, wait until May 28. Nearby ZIP codes are in USDA hardiness zone 6b.
- May 7Last spring frost (median)50% chance of 32°F after this date
- May 28Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 147 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 | May 12 | May 30 | Jun 17 |
| 32°F | Apr 24 | May 7 | May 28 |
| 28°F | Apr 1 | Apr 21 | May 6 |
| 24°F | Mar 4 | Mar 28 | Apr 15 |
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 1 | Sep 20 | Oct 4 |
| 32°F | Sep 16 | Oct 4 | Oct 17 |
| 28°F | Oct 1 | Oct 15 | Nov 2 |
| 24°F | Oct 12 | Oct 30 | 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 | 87 days | 111 days | 135 days |
| 32°F | 123 days | 147 days | 169 days |
| 28°F | 154 days | 177 days | 202 days |
| 24°F | 189 days | 216 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 |
|---|---|---|---|
| 97868 | 6b | -5 to 0°F | 8 km |
| 97880 | 6b | -5 to 0°F | 43 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 USC00356634, at 45.4756, -118.8253, elevation 524 m (1,720 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 118.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Pendleton Dwtn (22 km)
- Pendleton (24 km)
- Pendleton WFO (24 km)
- Pendleton Branch Exp. Station (31 km)
- Meacham (31 km)
- Hermiston Muni Airport (52 km)
- Hermiston 2 NW (57 km)
- Heppner (59 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.