Last spring frost
Apr 1
Frost Dates for Cougar, WA
First fall frost
Nov 18
Growing season
227 days
Hardiness zone
8b
In an average year around Cougar, WA, the last spring frost (32°F) is about Apr 1 and the first fall frost is about Nov 18, giving roughly a 227-day growing season. To be safe most years, wait until Mar 6 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 24 | May 2 | Apr 13 |
| Freeze (32°F) | May 2 | Apr 1 | Mar 6 |
| Hard (28°F) | Mar 21 | Feb 22 | Jan 9 |
| Severe (24°F) | Feb 28 | Jan 17 | Dec 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 24 | May 15 | May 10 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 20 | Apr 13 |
| 32°F | May 2 | Apr 23 | Apr 15 | Apr 6 | Apr 1 | Mar 29 | Mar 24 | Mar 16 | Mar 6 |
| 28°F | Mar 21 | Mar 11 | Mar 4 | Feb 28 | Feb 22 | Feb 17 | Feb 8 | Jan 29 | Jan 9 |
| 24°F | Feb 28 | Feb 18 | Feb 10 | Jan 30 | Jan 17 | Jan 10 | Jan 2 | Dec 22 | Dec 7 |
| 20°F | Feb 19 | Feb 11 | Jan 30 | Jan 13 | Jan 3 | Dec 26 | Dec 17 | Dec 9 | Dec 1 |
| 16°F | Feb 16 | Feb 1 | Jan 1 | Dec 24 | Dec 20 | Dec 15 | Dec 10 | Dec 5 | Nov 27 |
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 9 | Oct 29 | Nov 18 |
| Freeze (32°F) | Oct 29 | Nov 18 | Dec 8 |
| Hard (28°F) | Nov 12 | Dec 7 | Jan 10 |
| Severe (24°F) | Nov 22 | Dec 22 | Feb 13 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 9 | Oct 16 | Oct 21 | Oct 25 | Oct 29 | Nov 2 | Nov 6 | Nov 12 | Nov 18 |
| 32°F | Oct 29 | Nov 5 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 27 | Dec 2 | Dec 8 |
| 28°F | Nov 12 | Nov 20 | Nov 27 | Dec 2 | Dec 7 | Dec 12 | Dec 19 | Dec 27 | Jan 10 |
| 24°F | Nov 22 | Dec 1 | Dec 7 | Dec 14 | Dec 22 | Dec 30 | Jan 6 | Jan 17 | Feb 13 |
| 20°F | Nov 25 | Dec 1 | Dec 8 | Dec 15 | Dec 23 | Jan 1 | Jan 10 | Jan 27 | Feb 16 |
| 16°F | Nov 26 | Nov 30 | Dec 8 | Dec 12 | Dec 18 | Dec 22 | Dec 28 | Jan 14 | 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: Cougar 6 E, Wa, about 10.1 miles away@if(!empty($station['elevation_ft'])), at 659 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 Cougar, WA?
On average, the last spring frost (32°F) around Cougar, WA is about Apr 1. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 6.
When is the first frost in the fall?
The first fall frost around Cougar, WA typically arrives about Nov 18. 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 1 on average, or Mar 6 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 227 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 98603 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026