Frost dates for Mount Adams Ranger Station, WA
At Mount Adams Ranger Station, the median last spring frost (32°F) is May 18 and the median first fall frost is Sep 25, for a typical growing season of 125 days. For a 90% chance that the last frost has passed, wait until Jun 12. Nearby ZIP codes are in USDA hardiness zone 7a.
- May 18Last spring frost (median)50% chance of 32°F after this date
- Jun 12Safer planting date10% chance of 32°F after this date
- Sep 25First fall frost (median)50% chance of 32°F by this date
- 125 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 23 | Jun 13 | Jul 2 |
| 32°F | May 1 | May 18 | Jun 12 |
| 28°F | Apr 11 | Apr 29 | May 16 |
| 24°F | Mar 8 | Apr 1 | Apr 28 |
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 | Aug 20 | Sep 7 | Sep 25 |
| 32°F | Sep 4 | Sep 25 | Oct 10 |
| 28°F | Sep 21 | Oct 9 | Nov 1 |
| 24°F | Oct 5 | Oct 27 | Nov 18 |
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 | 55 days | 84 days | 111 days |
| 32°F | 93 days | 125 days | 151 days |
| 28°F | 131 days | 161 days | 191 days |
| 24°F | 173 days | 207 days | 241 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 |
|---|---|---|---|
| 98650 | 7a | 0 to 5°F | 6 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 USC00455659, at 45.9997, -121.5403, elevation 594 m (1,950 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 163.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Glenwood #2 (21 km)
- Snowden (25 km)
- Carson Fish Hatchery (37 km)
- The Dalles Muni Airport (51 km)
- Cougar 6 E (52 km)
- Goldendale (58 km)
- Skamania Fish Hatchery (67 km)
- Satus Pass 2 SSW (68 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.