Last spring frost
Apr 16
Frost Dates for Marblemount, WA
First fall frost
Oct 25
Growing season
192 days
Hardiness zone
7a
In an average year around Marblemount, WA, the last spring frost (32°F) is about Apr 16 and the first fall frost is about Oct 25, giving roughly a 192-day growing season. To be safe most years, wait until Mar 26 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 21 | May 6 | Apr 19 |
| Freeze (32°F) | May 6 | Apr 16 | Mar 26 |
| Hard (28°F) | Apr 6 | Mar 19 | Feb 27 |
| Severe (24°F) | Mar 14 | Feb 18 | Jan 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 21 | May 16 | May 12 | May 9 | May 6 | May 3 | Apr 30 | Apr 26 | Apr 19 |
| 32°F | May 6 | May 1 | Apr 26 | Apr 21 | Apr 16 | Apr 11 | Apr 6 | Mar 31 | Mar 26 |
| 28°F | Apr 6 | Mar 31 | Mar 27 | Mar 22 | Mar 19 | Mar 16 | Mar 12 | Mar 5 | Feb 27 |
| 24°F | Mar 14 | Mar 5 | Feb 28 | Feb 24 | Feb 18 | Feb 11 | Jan 31 | Jan 16 | Jan 2 |
| 20°F | Feb 24 | Feb 14 | Feb 1 | Jan 23 | Jan 15 | Jan 6 | Jan 1 | Dec 22 | Dec 9 |
| 16°F | Feb 19 | Feb 3 | Jan 22 | Jan 13 | Jan 2 | Dec 29 | Dec 18 | Dec 8 | Nov 30 |
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) | Sep 27 | Oct 10 | Oct 25 |
| Freeze (32°F) | Oct 10 | Oct 25 | Nov 11 |
| Hard (28°F) | Oct 22 | Nov 11 | Dec 6 |
| Severe (24°F) | Nov 11 | Dec 6 | Jan 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 25 |
| 32°F | Oct 10 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Nov 1 | Nov 5 | Nov 11 |
| 28°F | Oct 22 | Oct 29 | Nov 2 | Nov 6 | Nov 11 | Nov 17 | Nov 23 | Nov 29 | Dec 6 |
| 24°F | Nov 11 | Nov 21 | Nov 27 | Dec 1 | Dec 6 | Dec 13 | Dec 19 | Dec 27 | Jan 9 |
| 20°F | Nov 26 | Dec 1 | Dec 8 | Dec 15 | Dec 23 | Dec 29 | Jan 3 | Jan 14 | Jan 28 |
| 16°F | Nov 27 | Dec 2 | Dec 8 | Dec 17 | Dec 28 | Jan 1 | Jan 14 | Jan 25 | Feb 15 |
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: Darrington 21 Nne, Wa, about 13.3 miles away@if(!empty($station['elevation_ft'])), at 407 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 Marblemount, WA?
On average, the last spring frost (32°F) around Marblemount, WA is about Apr 16. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 26.
When is the first frost in the fall?
The first fall frost around Marblemount, WA typically arrives about Oct 25. 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 Apr 16 on average, or Mar 26 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 192 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 98267 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026