Last spring frost
May 16
Frost Dates for Bickleton, WA
First fall frost
Oct 9
Growing season
144 days
Hardiness zone
7b
In an average year around Bickleton, WA, the last spring frost (32°F) is about May 16 and the first fall frost is about Oct 9, giving roughly a 144-day growing season. To be safe most years, wait until Apr 28 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 29 | Jun 9 | May 17 |
| Freeze (32°F) | Jun 10 | May 16 | Apr 28 |
| Hard (28°F) | May 16 | Apr 27 | Apr 7 |
| Severe (24°F) | Apr 26 | Apr 1 | Mar 2 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 29 | Jun 21 | Jun 17 | Jun 13 | Jun 9 | Jun 4 | May 31 | May 24 | May 17 |
| 32°F | Jun 10 | Jun 2 | May 27 | May 21 | May 16 | May 13 | May 8 | May 3 | Apr 28 |
| 28°F | May 16 | May 9 | May 4 | Apr 30 | Apr 27 | Apr 23 | Apr 19 | Apr 14 | Apr 7 |
| 24°F | Apr 26 | Apr 18 | Apr 12 | Apr 5 | Apr 1 | Mar 27 | Mar 20 | Mar 11 | Mar 2 |
| 20°F | Mar 29 | Mar 21 | Mar 12 | Mar 6 | Mar 2 | Feb 27 | Feb 21 | Feb 15 | Feb 1 |
| 16°F | Mar 4 | Feb 28 | Feb 22 | Feb 17 | Feb 12 | Feb 4 | Jan 27 | Jan 17 | Jan 5 |
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 7 | Sep 29 | Oct 12 |
| Freeze (32°F) | Sep 26 | Oct 9 | Oct 26 |
| Hard (28°F) | Oct 6 | Oct 22 | Nov 8 |
| Severe (24°F) | Oct 17 | Nov 3 | Nov 21 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 7 | Sep 15 | Sep 22 | Sep 26 | Sep 29 | Oct 1 | Oct 3 | Oct 6 | Oct 12 |
| 32°F | Sep 26 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 16 | Oct 20 | Oct 26 |
| 28°F | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Nov 1 | Nov 8 |
| 24°F | Oct 17 | Oct 23 | Oct 27 | Oct 30 | Nov 3 | Nov 7 | Nov 11 | Nov 15 | Nov 21 |
| 20°F | Oct 26 | Nov 1 | Nov 7 | Nov 12 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 6 |
| 16°F | Nov 2 | Nov 11 | Nov 19 | Nov 25 | Nov 29 | Dec 3 | Dec 9 | Dec 16 | Dec 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: Bickleton, Wa, about 7.8 miles away@if(!empty($station['elevation_ft'])), at 3,015 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 Bickleton, WA?
On average, the last spring frost (32°F) around Bickleton, WA is about May 16. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 28.
When is the first frost in the fall?
The first fall frost around Bickleton, WA typically arrives about Oct 9. 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 16 on average, or Apr 28 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 144 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 99322 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026