Last spring frost
Mar 24
Frost Dates for Lake Cassidy, WA
First fall frost
Nov 2
Growing season
223 days
Hardiness zone
8b
In an average year around Lake Cassidy, WA, the last spring frost (32°F) is about Mar 24 and the first fall frost is about Nov 2, giving roughly a 223-day growing season. To be safe most years, wait until Mar 4 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 8 | Apr 20 | Mar 31 |
| Freeze (32°F) | Apr 11 | Mar 24 | Mar 4 |
| Hard (28°F) | Mar 20 | Mar 1 | Jan 31 |
| Severe (24°F) | Feb 28 | Jan 31 | Dec 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 8 | May 3 | Apr 29 | Apr 24 | Apr 20 | Apr 15 | Apr 10 | Apr 6 | Mar 31 |
| 32°F | Apr 11 | Apr 4 | Apr 1 | Mar 29 | Mar 24 | Mar 21 | Mar 17 | Mar 12 | Mar 4 |
| 28°F | Mar 20 | Mar 14 | Mar 8 | Mar 4 | Mar 1 | Feb 26 | Feb 21 | Feb 14 | Jan 31 |
| 24°F | Feb 28 | Feb 25 | Feb 17 | Feb 9 | Jan 31 | Jan 20 | Jan 9 | Jan 1 | Dec 15 |
| 20°F | Feb 14 | Feb 1 | Jan 21 | Jan 8 | Jan 1 | Dec 25 | Dec 16 | Dec 9 | Dec 1 |
| 16°F | Jan 31 | Jan 6 | Jan 3 | Jan 1 | Dec 28 | Dec 16 | Dec 9 | Dec 6 | Nov 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) | Oct 1 | Oct 18 | Nov 4 |
| Freeze (32°F) | Oct 16 | Nov 2 | Nov 23 |
| Hard (28°F) | Oct 29 | Nov 21 | Dec 14 |
| Severe (24°F) | Nov 12 | Dec 5 | Jan 11 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 1 | Oct 6 | Oct 11 | Oct 15 | Oct 18 | Oct 22 | Oct 25 | Oct 30 | Nov 4 |
| 32°F | Oct 16 | Oct 22 | Oct 27 | Oct 31 | Nov 2 | Nov 6 | Nov 11 | Nov 17 | Nov 23 |
| 28°F | Oct 29 | Nov 5 | Nov 11 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 4 | Dec 14 |
| 24°F | Nov 12 | Nov 20 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 18 | Dec 28 | Jan 11 |
| 20°F | Nov 23 | Nov 30 | Dec 4 | Dec 9 | Dec 15 | Dec 23 | Dec 31 | Jan 6 | Jan 30 |
| 16°F | Nov 26 | Dec 1 | Dec 7 | Dec 11 | Dec 21 | Dec 30 | Jan 1 | Jan 5 | Jan 26 |
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: Everett, Wa, about 6.6 miles away@if(!empty($station['elevation_ft'])), at 60 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 Lake Cassidy, WA?
On average, the last spring frost (32°F) around Lake Cassidy, WA is about Mar 24. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 4.
When is the first frost in the fall?
The first fall frost around Lake Cassidy, WA typically arrives about Nov 2. 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 24 on average, or Mar 4 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 223 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 98258 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026