Last spring frost
Mar 24
Frost Dates for Conway, WA
First fall frost
Nov 3
Growing season
224 days
Hardiness zone
8b
In an average year around Conway, WA, the last spring frost (32°F) is about Mar 24 and the first fall frost is about Nov 3, giving roughly a 224-day growing season. To be safe most years, wait until Mar 3 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 5 | Apr 18 | Mar 29 |
| Freeze (32°F) | Apr 14 | Mar 24 | Mar 3 |
| Hard (28°F) | Mar 17 | Feb 27 | Jan 23 |
| Severe (24°F) | Feb 28 | Feb 3 | Dec 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 30 | Apr 27 | Apr 22 | Apr 18 | Apr 15 | Apr 10 | Apr 4 | Mar 29 |
| 32°F | Apr 14 | Apr 7 | Apr 1 | Mar 28 | Mar 24 | Mar 20 | Mar 15 | Mar 10 | Mar 3 |
| 28°F | Mar 17 | Mar 12 | Mar 6 | Mar 1 | Feb 27 | Feb 23 | Feb 18 | Feb 10 | Jan 23 |
| 24°F | Feb 28 | Feb 24 | Feb 19 | Feb 12 | Feb 3 | Jan 27 | Jan 15 | Jan 4 | Dec 19 |
| 20°F | Feb 21 | Feb 11 | Jan 31 | Jan 20 | Jan 12 | Jan 4 | Dec 31 | Dec 21 | Dec 9 |
| 16°F | Feb 4 | Jan 25 | Jan 14 | Jan 7 | Jan 3 | Dec 31 | Dec 25 | Dec 20 | Dec 9 |
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 29 | Oct 16 | Nov 6 |
| Freeze (32°F) | Oct 12 | Nov 3 | Nov 25 |
| Hard (28°F) | Oct 31 | Nov 25 | Dec 23 |
| Severe (24°F) | Nov 13 | Dec 15 | Jan 29 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 29 | Oct 3 | Oct 7 | Oct 11 | Oct 16 | Oct 19 | Oct 24 | Oct 30 | Nov 6 |
| 32°F | Oct 12 | Oct 21 | Oct 26 | Oct 31 | Nov 3 | Nov 8 | Nov 13 | Nov 19 | Nov 25 |
| 28°F | Oct 31 | Nov 7 | Nov 13 | Nov 19 | Nov 25 | Nov 30 | Dec 4 | Dec 13 | Dec 23 |
| 24°F | Nov 13 | Nov 23 | Dec 1 | Dec 6 | Dec 15 | Dec 22 | Dec 30 | Jan 8 | Jan 29 |
| 20°F | Nov 24 | Dec 5 | Dec 12 | Dec 20 | Dec 28 | Jan 1 | Jan 9 | Jan 24 | Feb 9 |
| 16°F | Dec 5 | Dec 13 | Dec 21 | Dec 27 | Dec 31 | Jan 2 | Jan 9 | Jan 15 | Feb 1 |
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: Mt Vernon 3 Wnw, Wa, about 7.5 miles away@if(!empty($station['elevation_ft'])), at 14 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 Conway, WA?
On average, the last spring frost (32°F) around Conway, WA is about Mar 24. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 3.
When is the first frost in the fall?
The first fall frost around Conway, WA typically arrives about Nov 3. 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 3 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 224 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 98238 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026