Last spring frost
Apr 27
Frost Dates for Cascade Valley, WA
First fall frost
Oct 8
Growing season
165 days
Hardiness zone
7a
In an average year around Cascade Valley, WA, the last spring frost (32°F) is about Apr 27 and the first fall frost is about Oct 8, giving roughly a 165-day growing season. To be safe most years, wait until Apr 10 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 23 | May 9 | Apr 27 |
| Freeze (32°F) | May 11 | Apr 27 | Apr 10 |
| Hard (28°F) | Apr 30 | Apr 10 | Mar 21 |
| Severe (24°F) | Apr 10 | Mar 16 | Feb 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 23 | May 18 | May 14 | May 11 | May 9 | May 6 | May 3 | Apr 30 | Apr 27 |
| 32°F | May 11 | May 6 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 16 | Apr 10 |
| 28°F | Apr 30 | Apr 23 | Apr 18 | Apr 14 | Apr 10 | Apr 6 | Apr 1 | Mar 29 | Mar 21 |
| 24°F | Apr 10 | Apr 2 | Mar 29 | Mar 23 | Mar 16 | Mar 12 | Mar 7 | Mar 3 | Feb 25 |
| 20°F | Mar 19 | Mar 11 | Mar 4 | Feb 28 | Feb 25 | Feb 20 | Feb 15 | Feb 9 | Jan 31 |
| 16°F | Mar 4 | Feb 26 | Feb 20 | Feb 13 | Feb 7 | Feb 2 | Jan 27 | Jan 16 | Jan 3 |
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 17 | Sep 29 | Oct 10 |
| Freeze (32°F) | Sep 29 | Oct 8 | Oct 23 |
| Hard (28°F) | Oct 5 | Oct 20 | Nov 5 |
| Severe (24°F) | Oct 17 | Nov 1 | Nov 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 21 | Sep 24 | Sep 27 | Sep 29 | Oct 1 | Oct 2 | Oct 5 | Oct 10 |
| 32°F | Sep 29 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 15 | Oct 18 | Oct 23 |
| 28°F | Oct 5 | Oct 11 | Oct 15 | Oct 17 | Oct 20 | Oct 23 | Oct 27 | Oct 30 | Nov 5 |
| 24°F | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 3 | Nov 7 | Nov 12 | Nov 18 |
| 20°F | Oct 24 | Oct 30 | Nov 3 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 30 |
| 16°F | Nov 2 | Nov 10 | Nov 16 | Nov 22 | Nov 26 | Nov 30 | Dec 4 | Dec 11 | Dec 22 |
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: Moses Lake Grant Co Ap, Wa, about 4.2 miles away@if(!empty($station['elevation_ft'])), at 1,196 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 Cascade Valley, WA?
On average, the last spring frost (32°F) around Cascade Valley, WA is about Apr 27. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 10.
When is the first frost in the fall?
The first fall frost around Cascade Valley, WA typically arrives about Oct 8. 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 27 on average, or Apr 10 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 165 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 98837 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026