Frost dates for Oregon City, OR
At Oregon City, the median last spring frost (32°F) is Mar 18 and the median first fall frost is Nov 18, for a typical growing season of 244 days. For a 90% chance that the last frost has passed, wait until Apr 11. Nearby ZIP codes are in USDA hardiness zones 8b to 9a.
- Mar 18Last spring frost (median)50% chance of 32°F after this date
- Apr 11Safer planting date10% chance of 32°F after this date
- Nov 18First fall frost (median)50% chance of 32°F by this date
- 244 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 | Mar 26 | Apr 15 | May 4 |
| 32°F | Feb 19 | Mar 18 | Apr 11 |
| 28°F | Jan 1 | Feb 12 | Mar 7 |
| 24°F | Dec 12 | Jan 16 | Feb 21 |
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 | Oct 16 | Oct 31 | Nov 20 |
| 32°F | Oct 30 | Nov 18 | Dec 12 |
| 28°F | Nov 16 | Dec 8 | Jan 5 |
| 24°F | Nov 29 | Dec 26 | Feb 4 |
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 | 173 days | 198 days | 226 days |
| 32°F | 214 days | 244 days | 280 days |
| 28°F | 264 days | 302 days | 342 days |
| 24°F | 309 days | 347 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 97% |
| 24°F | 69% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 97027 | 9a | 20 to 25°F | 3 km |
| 97068 | 9a | 20 to 25°F | 5 km |
| 97267 | 9a | 20 to 25°F | 6 km |
| 97045 | 9a | 20 to 25°F | 7 km |
| 97034 | 9a | 20 to 25°F | 9 km |
| 97015 | 9a | 20 to 25°F | 9 km |
| 97222 | 9a | 20 to 25°F | 9 km |
| 97086 | 8b | 15 to 20°F | 12 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 USC00356334, at 45.3558, -122.6047, elevation 51 m (167 ft).
- Data quality: Standard (24+ years of data), 24 years of freeze data.
- Average days per year at or below 32°F: 30.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- N Willamette Exp. Station (14 km)
- Aurora State Airport (18 km)
- Portland Kgw-Tv (19 km)
- Beaverton 2 SSW (20 km)
- Molalla 7ne (21 km)
- Portland WFO (23 km)
- Nature Park-Beaverton (24 km)
- Estacada 2 SE (24 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.