Frost dates for Saint Helens Rfd, OR
At Saint Helens Rfd, the median last spring frost (32°F) is Apr 18 and the median first fall frost is Nov 7, for a typical growing season of 201 days. For a 90% chance that the last frost has passed, wait until May 26. Nearby ZIP codes are in USDA hardiness zone 8b.
- Apr 18Last spring frost (median)50% chance of 32°F after this date
- May 26Safer planting date10% chance of 32°F after this date
- Nov 7First fall frost (median)50% chance of 32°F by this date
- 201 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 18 | May 6 | Jun 9 |
| 32°F | Mar 20 | Apr 18 | May 26 |
| 28°F | Feb 20 | Mar 24 | May 6 |
| 24°F | Jan 7 | Feb 24 | Apr 6 |
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 6 | Oct 24 | Nov 10 |
| 32°F | Oct 21 | Nov 7 | Nov 26 |
| 28°F | Nov 3 | Nov 24 | Dec 16 |
| 24°F | Nov 15 | Dec 12 | Jan 16 |
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 | 133 days | 168 days | 194 days |
| 32°F | 164 days | 201 days | 235 days |
| 28°F | 196 days | 244 days | 285 days |
| 24°F | 244 days | 292 days | 335 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 |
|---|---|---|---|
| 97053 | 8b | 15 to 20°F | 2 km |
| 97051 | 8b | 15 to 20°F | 6 km |
| 97018 | 8b | 15 to 20°F | 7 km |
| 97054 | 8b | 15 to 20°F | 13 km |
| 98674 | 8b | 15 to 20°F | 20 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 USC00357466, at 45.8489, -122.8722, elevation 82 m (269 ft).
- Data quality: Representative (10+ years), 16 years of freeze data.
- Average days per year at or below 32°F: 58.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Scappoose Ind Airport (9 km)
- Vernonia #2 (25 km)
- Portland-Hillsboro Airport (35 km)
- Portland Intl Airport (36 km)
- Clatskanie (39 km)
- Nature Park-Beaverton (39 km)
- Portland Kgw-Tv (39 km)
- Forest Grove (40 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.