Last spring frost
Apr 29
Frost Dates for Tumwater, WA
First fall frost
Oct 14
Growing season
169 days
Hardiness zone
8a
In an average year around Tumwater, WA, the last spring frost (32°F) is about Apr 29 and the first fall frost is about Oct 14, giving roughly a 169-day growing season. To be safe most years, wait until Apr 11 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 31 | May 15 | Apr 30 |
| Freeze (32°F) | May 15 | Apr 29 | Apr 11 |
| Hard (28°F) | Apr 29 | Apr 5 | Mar 12 |
| Severe (24°F) | Apr 1 | Mar 6 | Feb 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 31 | May 26 | May 22 | May 18 | May 15 | May 12 | May 8 | May 5 | Apr 30 |
| 32°F | May 15 | May 9 | May 5 | May 2 | Apr 29 | Apr 27 | Apr 23 | Apr 18 | Apr 11 |
| 28°F | Apr 29 | Apr 21 | Apr 15 | Apr 10 | Apr 5 | Apr 1 | Mar 28 | Mar 22 | Mar 12 |
| 24°F | Apr 1 | Mar 25 | Mar 18 | Mar 12 | Mar 6 | Mar 1 | Feb 25 | Feb 18 | Feb 7 |
| 20°F | Mar 8 | Feb 27 | Feb 22 | Feb 17 | Feb 12 | Feb 4 | Jan 22 | Jan 5 | Dec 19 |
| 16°F | Feb 23 | Feb 16 | Feb 10 | Feb 2 | Jan 17 | Jan 2 | Dec 24 | Dec 12 | Dec 2 |
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 12 | Sep 28 | Oct 14 |
| Freeze (32°F) | Sep 28 | Oct 14 | Nov 1 |
| Hard (28°F) | Oct 9 | Nov 1 | Nov 24 |
| Severe (24°F) | Oct 28 | Nov 20 | Dec 21 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 12 | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 5 | Oct 9 | Oct 14 |
| 32°F | Sep 28 | Oct 3 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 26 | Nov 1 |
| 28°F | Oct 9 | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 5 | Nov 10 | Nov 15 | Nov 24 |
| 24°F | Oct 28 | Nov 2 | Nov 9 | Nov 14 | Nov 20 | Nov 25 | Dec 1 | Dec 7 | Dec 21 |
| 20°F | Nov 6 | Nov 15 | Nov 23 | Nov 30 | Dec 6 | Dec 14 | Dec 26 | Jan 2 | Jan 29 |
| 16°F | Nov 15 | Nov 27 | Dec 4 | Dec 11 | Dec 18 | Dec 28 | Jan 5 | Jan 26 | 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: Olympia Ap, Wa, about 1.3 miles away@if(!empty($station['elevation_ft'])), at 188 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 Tumwater, WA?
On average, the last spring frost (32°F) around Tumwater, WA is about Apr 29. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 11.
When is the first frost in the fall?
The first fall frost around Tumwater, WA typically arrives about Oct 14. 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 29 on average, or Apr 11 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 169 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 98501 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026