Last spring frost
May 14
Frost Dates for Snoqualmie Pass, WA
First fall frost
Oct 17
Growing season
154 days
Hardiness zone
7a
In an average year around Snoqualmie Pass, WA, the last spring frost (32°F) is about May 14 and the first fall frost is about Oct 17, giving roughly a 154-day growing season. To be safe most years, wait until Apr 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) | Jun 30 | Jun 10 | May 20 |
| Freeze (32°F) | Jun 5 | May 14 | Apr 26 |
| Hard (28°F) | May 12 | Apr 21 | Mar 31 |
| Severe (24°F) | Apr 17 | Mar 24 | Mar 1 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 23 | Jun 19 | Jun 15 | Jun 10 | Jun 5 | Jun 1 | May 28 | May 20 |
| 32°F | Jun 5 | May 31 | May 24 | May 19 | May 14 | May 10 | May 6 | May 1 | Apr 26 |
| 28°F | May 12 | May 5 | May 1 | Apr 27 | Apr 21 | Apr 16 | Apr 12 | Apr 5 | Mar 31 |
| 24°F | Apr 17 | Apr 5 | Mar 31 | Mar 28 | Mar 24 | Mar 19 | Mar 14 | Mar 9 | Mar 1 |
| 20°F | Mar 22 | Mar 13 | Mar 8 | Mar 4 | Mar 1 | Feb 23 | Feb 16 | Feb 6 | Jan 24 |
| 16°F | Mar 5 | Feb 28 | Feb 21 | Feb 15 | Feb 8 | Feb 1 | Jan 22 | Jan 11 | Dec 29 |
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 14 | Oct 2 | Oct 15 |
| Freeze (32°F) | Oct 1 | Oct 17 | Nov 1 |
| Hard (28°F) | Oct 18 | Nov 2 | Nov 18 |
| Severe (24°F) | Oct 30 | Nov 16 | Dec 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 14 | Sep 21 | Sep 26 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 15 |
| 32°F | Oct 1 | Oct 6 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 27 | Nov 1 |
| 28°F | Oct 18 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 18 |
| 24°F | Oct 30 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 23 | Nov 26 | Dec 2 |
| 20°F | Nov 7 | Nov 15 | Nov 20 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 11 | Dec 18 |
| 16°F | Nov 18 | Nov 25 | Dec 1 | Dec 5 | Dec 10 | Dec 16 | Dec 23 | Jan 1 | Jan 13 |
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: Stampede Pass, Wa, about 10.9 miles away@if(!empty($station['elevation_ft'])), at 3,959 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 Snoqualmie Pass, WA?
On average, the last spring frost (32°F) around Snoqualmie Pass, WA is about May 14. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 26.
When is the first frost in the fall?
The first fall frost around Snoqualmie Pass, WA typically arrives about Oct 17. 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 May 14 on average, or Apr 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 154 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 98068 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026