Last spring frost
Apr 2
Frost Dates for Marblemount, WA
First fall frost
Nov 14
Growing season
224 days
Hardiness zone
7a
In an average year around Marblemount, WA, the last spring frost (32°F) is about Apr 2 and the first fall frost is about Nov 14, giving roughly a 224-day growing season. To be safe most years, wait until Mar 9 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 14 | Apr 27 | Apr 10 |
| Freeze (32°F) | Apr 27 | Apr 2 | Mar 9 |
| Hard (28°F) | Mar 25 | Mar 2 | Jan 24 |
| Severe (24°F) | Mar 6 | Jan 31 | Dec 24 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 14 | May 8 | May 4 | Apr 30 | Apr 27 | Apr 23 | Apr 19 | Apr 15 | Apr 10 |
| 32°F | Apr 27 | Apr 17 | Apr 9 | Apr 5 | Apr 2 | Mar 29 | Mar 24 | Mar 18 | Mar 9 |
| 28°F | Mar 25 | Mar 18 | Mar 11 | Mar 7 | Mar 2 | Feb 26 | Feb 20 | Feb 8 | Jan 24 |
| 24°F | Mar 6 | Feb 26 | Feb 18 | Feb 9 | Jan 31 | Jan 24 | Jan 14 | Jan 5 | Dec 24 |
| 20°F | Feb 20 | Feb 7 | Jan 29 | Jan 23 | Jan 14 | Jan 7 | Jan 2 | Dec 21 | Dec 8 |
| 16°F | Jan 31 | Jan 25 | Jan 17 | Jan 11 | Jan 6 | Dec 31 | Dec 23 | Dec 13 | Dec 8 |
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 18 | Oct 30 | Nov 14 |
| Freeze (32°F) | Oct 28 | Nov 14 | Dec 5 |
| Hard (28°F) | Nov 12 | Dec 4 | Jan 7 |
| Severe (24°F) | Nov 24 | Dec 22 | Jan 30 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 18 | Oct 21 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 8 | Nov 14 |
| 32°F | Oct 28 | Nov 3 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 21 | Nov 26 | Dec 5 |
| 28°F | Nov 12 | Nov 18 | Nov 24 | Nov 28 | Dec 4 | Dec 9 | Dec 16 | Dec 27 | Jan 7 |
| 24°F | Nov 24 | Dec 1 | Dec 7 | Dec 13 | Dec 22 | Dec 28 | Jan 4 | Jan 15 | Jan 30 |
| 20°F | Nov 28 | Dec 6 | Dec 11 | Dec 19 | Dec 27 | Jan 1 | Jan 9 | Jan 21 | Jan 31 |
| 16°F | Dec 1 | Dec 8 | Dec 14 | Dec 23 | Dec 29 | Jan 2 | Jan 10 | Jan 16 | Jan 27 |
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: Newhalem, Wa, about 9.1 miles away@if(!empty($station['elevation_ft'])), at 525 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 2. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 9.
When is the first frost in the fall?
The first fall frost around Marblemount, WA typically arrives about Nov 14. 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 2 on average, or Mar 9 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 224 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 98283 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026