Frost dates for Cascadia, OR
At Cascadia, the median last spring frost (32°F) is Apr 29 and the median first fall frost is Oct 13, for a typical growing season of 167 days. For a 90% chance that the last frost has passed, wait until May 17. Nearby ZIP codes are in USDA hardiness zone 8b.
- Apr 29Last spring frost (median)50% chance of 32°F after this date
- May 17Safer planting date10% chance of 32°F after this date
- Oct 13First fall frost (median)50% chance of 32°F by this date
- 167 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 2 | May 21 | Jun 12 |
| 32°F | Apr 5 | Apr 29 | May 17 |
| 28°F | Feb 26 | Mar 30 | Apr 28 |
| 24°F | Dec 31 | Feb 19 | Mar 23 |
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 30 | Sep 21 | Oct 14 |
| 32°F | Sep 22 | Oct 13 | Nov 6 |
| 28°F | Oct 12 | Nov 5 | Dec 4 |
| 24°F | Oct 31 | Dec 1 | Jan 6 |
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 | 88 days | 121 days | 153 days |
| 32°F | 136 days | 167 days | 199 days |
| 28°F | 184 days | 220 days | 263 days |
| 24°F | 244 days | 292 days | 336 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 98% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 97329 | 8b | 15 to 20°F | 15 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 USC00351433, at 44.3914, -122.4811, elevation 293 m (960 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 79.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Foster Dam (15 km)
- Lacomb 3 NNE (32 km)
- Cougar Dam (35 km)
- Leaburg 1 SW (36 km)
- Lebanon (37 km)
- Belknap Springs 8 N (37 km)
- McKenzie River Ranger Station (37 km)
- Detroit Dam (41 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.