Frost dates for Mount Vernon 3 WNW, WA
At Mount Vernon 3 WNW, the median last spring frost (32°F) is Mar 24 and the median first fall frost is Nov 3, for a typical growing season of 224 days. For a 90% chance that the last frost has passed, wait until Apr 14. Nearby ZIP codes are in USDA hardiness zone 8b.
- Mar 24Last spring frost (median)50% chance of 32°F after this date
- Apr 14Safer planting date10% chance of 32°F after this date
- Nov 3First fall frost (median)50% chance of 32°F by this date
- 224 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 29 | Apr 18 | May 5 |
| 32°F | Mar 3 | Mar 24 | Apr 14 |
| 28°F | Jan 23 | Feb 27 | Mar 17 |
| 24°F | Dec 19 | Feb 3 | Feb 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 | Sep 29 | Oct 16 | Nov 6 |
| 32°F | Oct 12 | Nov 3 | Nov 25 |
| 28°F | Oct 31 | Nov 25 | Dec 23 |
| 24°F | Nov 13 | Dec 15 | Jan 29 |
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 | 156 days | 182 days | 208 days |
| 32°F | 196 days | 224 days | 256 days |
| 28°F | 239 days | 273 days | 310 days |
| 24°F | 275 days | 316 days | 362 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 92% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 98273 | 8b | 15 to 20°F | 4 km |
| 98233 | 8b | 15 to 20°F | 7 km |
| 98257 | 8b | 15 to 20°F | 10 km |
| 98238 | 8b | 15 to 20°F | 12 km |
| 98232 | 8b | 15 to 20°F | 14 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 USC00455678, at 48.4403, -122.3867, elevation 4 m (14 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 46.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sedro-Woolley (13 km)
- Anacortes (19 km)
- Whidbey Island NAS (23 km)
- Bellingham 3 SSW (32 km)
- Arlington (33 km)
- Coupeville 1 S (34 km)
- Olga 2 SE (36 km)
- Bellingham Intl Airport (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.