Last spring frost
Apr 26
Frost Dates for Humptulips, WA
First fall frost
Oct 22
Growing season
180 days
Hardiness zone
8b
In an average year around Humptulips, WA, the last spring frost (32°F) is about Apr 26 and the first fall frost is about Oct 22, giving roughly a 180-day growing season. To be safe most years, wait until Mar 31 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 3 | May 16 | Apr 28 |
| Freeze (32°F) | May 15 | Apr 26 | Mar 31 |
| Hard (28°F) | Apr 22 | Mar 27 | Feb 21 |
| Severe (24°F) | Mar 19 | Feb 16 | Dec 12 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 3 | May 29 | May 24 | May 20 | May 16 | May 12 | May 6 | May 2 | Apr 28 |
| 32°F | May 15 | May 7 | May 3 | Apr 30 | Apr 26 | Apr 21 | Apr 16 | Apr 9 | Mar 31 |
| 28°F | Apr 22 | Apr 11 | Apr 5 | Mar 31 | Mar 27 | Mar 20 | Mar 13 | Mar 3 | Feb 21 |
| 24°F | Mar 19 | Mar 7 | Feb 28 | Feb 22 | Feb 16 | Feb 7 | Jan 19 | Dec 31 | Dec 12 |
| 20°F | Feb 22 | Feb 11 | Jan 29 | Jan 14 | Jan 2 | Dec 24 | Dec 14 | Dec 7 | Nov 30 |
| 16°F | Jan 28 | Jan 13 | Dec 31 | Dec 25 | Dec 20 | Dec 15 | Dec 11 | Dec 5 | Dec 1 |
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 16 | Oct 3 | Oct 22 |
| Freeze (32°F) | Oct 3 | Oct 22 | Nov 15 |
| Hard (28°F) | Oct 21 | Nov 13 | Dec 15 |
| Severe (24°F) | Nov 7 | Dec 7 | Jan 29 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 16 | Sep 24 | Sep 28 | Oct 1 | Oct 3 | Oct 7 | Oct 10 | Oct 15 | Oct 22 |
| 32°F | Oct 3 | Oct 9 | Oct 14 | Oct 19 | Oct 22 | Oct 26 | Oct 30 | Nov 4 | Nov 15 |
| 28°F | Oct 21 | Oct 28 | Nov 1 | Nov 6 | Nov 13 | Nov 20 | Nov 28 | Dec 4 | Dec 15 |
| 24°F | Nov 7 | Nov 16 | Nov 24 | Dec 1 | Dec 7 | Dec 14 | Dec 24 | Jan 2 | Jan 29 |
| 20°F | Nov 19 | Nov 30 | Dec 3 | Dec 10 | Dec 16 | Dec 24 | Jan 1 | Jan 16 | Feb 10 |
| 16°F | Nov 29 | Dec 3 | Dec 8 | Dec 12 | Dec 18 | Dec 22 | Dec 29 | Jan 10 | Jan 28 |
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: Humptulips Salmon Hatchery, Wa, about 6.1 miles away@if(!empty($station['elevation_ft'])), at 140 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 Humptulips, WA?
On average, the last spring frost (32°F) around Humptulips, WA is about Apr 26. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 31.
When is the first frost in the fall?
The first fall frost around Humptulips, WA typically arrives about Oct 22. 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 26 on average, or Mar 31 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 180 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 98552 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026