Frost dates for Clearbrook, WA
At Clearbrook, the median last spring frost (32°F) is Apr 18 and the median first fall frost is Oct 18, for a typical growing season of 185 days. For a 90% chance that the last frost has passed, wait until May 5. Nearby ZIP codes are in USDA hardiness zone 8a.
- Apr 18Last spring frost (median)50% chance of 32°F after this date
- May 5Safer planting date10% chance of 32°F after this date
- Oct 18First fall frost (median)50% chance of 32°F by this date
- 185 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 23 | May 7 | May 22 |
| 32°F | Mar 27 | Apr 18 | May 5 |
| 28°F | Feb 25 | Mar 18 | Apr 8 |
| 24°F | Jan 10 | Feb 21 | Mar 12 |
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 10 | Sep 29 | Oct 14 |
| 32°F | Sep 28 | Oct 18 | Nov 8 |
| 28°F | Oct 20 | Nov 7 | Dec 4 |
| 24°F | Nov 6 | Dec 1 | Dec 30 |
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 | 121 days | 143 days | 166 days |
| 32°F | 155 days | 185 days | 215 days |
| 28°F | 202 days | 235 days | 270 days |
| 24°F | 251 days | 288 days | 328 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 |
|---|---|---|---|
| 98276 | 8a | 10 to 15°F | 4 km |
| 98247 | 8a | 10 to 15°F | 8 km |
| 98264 | 8a | 10 to 15°F | 9 km |
| 98295 | 8a | 10 to 15°F | 10 km |
| 98266 | 8a | 10 to 15°F | 21 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 USC00451484, at 48.9672, -122.3292, elevation 20 m (64 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 57.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Bellingham Intl Airport (25 km)
- Bellingham 3 SSW (31 km)
- Blaine (34 km)
- Olga 2 SE (53 km)
- Sedro-Woolley (53 km)
- Anacortes (55 km)
- Upper Baker Dam (58 km)
- Mount Vernon 3 WNW (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.