Last spring frost
Mar 31
Frost Dates for Birch Bay, WA
First fall frost
Nov 4
Growing season
219 days
Hardiness zone
8b
In an average year around Birch Bay, WA, the last spring frost (32°F) is about Mar 31 and the first fall frost is about Nov 4, giving roughly a 219-day growing season. To be safe most years, wait until Mar 8 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 12 | Apr 23 | Apr 1 |
| Freeze (32°F) | Apr 22 | Mar 31 | Mar 8 |
| Hard (28°F) | Mar 31 | Mar 5 | Feb 2 |
| Severe (24°F) | Mar 8 | Feb 10 | Jan 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 12 | May 4 | May 1 | Apr 28 | Apr 23 | Apr 17 | Apr 12 | Apr 7 | Apr 1 |
| 32°F | Apr 22 | Apr 12 | Apr 7 | Apr 3 | Mar 31 | Mar 26 | Mar 21 | Mar 15 | Mar 8 |
| 28°F | Mar 31 | Mar 21 | Mar 15 | Mar 10 | Mar 5 | Feb 28 | Feb 25 | Feb 17 | Feb 2 |
| 24°F | Mar 8 | Feb 28 | Feb 25 | Feb 18 | Feb 10 | Jan 31 | Jan 23 | Jan 12 | Jan 2 |
| 20°F | Feb 25 | Feb 16 | Feb 3 | Jan 27 | Jan 18 | Jan 11 | Jan 3 | Dec 25 | Dec 8 |
| 16°F | Feb 12 | Jan 30 | Jan 25 | Jan 16 | Jan 9 | Jan 2 | Dec 28 | Dec 17 | Dec 7 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 4 | Oct 20 | Nov 6 |
| Freeze (32°F) | Oct 18 | Nov 4 | Nov 24 |
| Hard (28°F) | Oct 30 | Nov 19 | Dec 16 |
| Severe (24°F) | Nov 12 | Dec 6 | Jan 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 4 | Oct 8 | Oct 12 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Oct 31 | Nov 6 |
| 32°F | Oct 18 | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 8 | Nov 12 | Nov 17 | Nov 24 |
| 28°F | Oct 30 | Nov 6 | Nov 11 | Nov 15 | Nov 19 | Nov 24 | Nov 28 | Dec 5 | Dec 16 |
| 24°F | Nov 12 | Nov 20 | Nov 26 | Dec 1 | Dec 6 | Dec 12 | Dec 21 | Dec 31 | Jan 15 |
| 20°F | Nov 25 | Dec 1 | Dec 6 | Dec 13 | Dec 23 | Dec 30 | Jan 7 | Jan 17 | Feb 1 |
| 16°F | Dec 4 | Dec 10 | Dec 20 | Dec 26 | Jan 1 | Jan 5 | Jan 12 | Jan 24 | Jan 31 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Blaine, Wa, about 4.3 miles away@if(!empty($station['elevation_ft'])), at 60 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Birch Bay, WA?
On average, the last spring frost (32°F) around Birch Bay, WA is about Mar 31. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 8.
When is the first frost in the fall?
The first fall frost around Birch Bay, WA typically arrives about Nov 4. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 31 on average, or Mar 8 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 219 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 98230 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026