Last spring frost
Mar 17
Frost Dates for Coupeville, WA
First fall frost
Nov 11
Growing season
237 days
Hardiness zone
8b
In an average year around Coupeville, WA, the last spring frost (32°F) is about Mar 17 and the first fall frost is about Nov 11, giving roughly a 237-day growing season. To be safe most years, wait until Feb 24 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) | Apr 30 | Apr 13 | Mar 27 |
| Freeze (32°F) | Apr 3 | Mar 17 | Feb 24 |
| Hard (28°F) | Mar 12 | Feb 21 | Jan 11 |
| Severe (24°F) | Feb 27 | Jan 18 | Dec 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 30 | Apr 25 | Apr 20 | Apr 16 | Apr 13 | Apr 9 | Apr 5 | Apr 2 | Mar 27 |
| 32°F | Apr 3 | Mar 30 | Mar 26 | Mar 21 | Mar 17 | Mar 11 | Mar 7 | Mar 2 | Feb 24 |
| 28°F | Mar 12 | Mar 6 | Mar 1 | Feb 26 | Feb 21 | Feb 17 | Feb 11 | Jan 31 | Jan 11 |
| 24°F | Feb 27 | Feb 18 | Feb 11 | Jan 31 | Jan 18 | Jan 8 | Jan 1 | Dec 22 | Dec 6 |
| 20°F | Feb 15 | Jan 31 | Jan 16 | Jan 6 | Dec 31 | Dec 22 | Dec 13 | Dec 5 | Nov 28 |
| 16°F | Jan 12 | Jan 1 | Dec 25 | Dec 17 | Dec 11 | Dec 6 | Dec 3 | Nov 30 | Nov 23 |
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 7 | Oct 27 | Nov 13 |
| Freeze (32°F) | Oct 21 | Nov 11 | Dec 1 |
| Hard (28°F) | Nov 6 | Nov 28 | Dec 30 |
| Severe (24°F) | Nov 16 | Dec 12 | Jan 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 7 | Oct 14 | Oct 18 | Oct 22 | Oct 27 | Oct 30 | Nov 2 | Nov 6 | Nov 13 |
| 32°F | Oct 21 | Oct 30 | Nov 3 | Nov 7 | Nov 11 | Nov 16 | Nov 20 | Nov 25 | Dec 1 |
| 28°F | Nov 6 | Nov 12 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 7 | Dec 16 | Dec 30 |
| 24°F | Nov 16 | Nov 25 | Nov 30 | Dec 5 | Dec 12 | Dec 19 | Dec 29 | Jan 6 | Jan 28 |
| 20°F | Nov 19 | Nov 28 | Dec 2 | Dec 9 | Dec 16 | Dec 24 | Jan 1 | Jan 14 | Feb 1 |
| 16°F | Nov 23 | Nov 29 | Dec 2 | Dec 6 | Dec 9 | Dec 15 | Dec 23 | Jan 1 | Jan 8 |
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: Coupeville 1 S, Wa, about 1.8 miles away@if(!empty($station['elevation_ft'])), at 50 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 Coupeville, WA?
On average, the last spring frost (32°F) around Coupeville, WA is about Mar 17. In cooler years it can run later, so for a safer bet many gardeners wait until Feb 24.
When is the first frost in the fall?
The first fall frost around Coupeville, WA typically arrives about Nov 11. 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 17 on average, or Feb 24 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 237 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 98239 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026