Last spring frost
May 10
Frost Dates for Reardan, WA
First fall frost
Sep 26
Growing season
137 days
Hardiness zone
6b
In an average year around Reardan, WA, the last spring frost (32°F) is about May 10 and the first fall frost is about Sep 26, giving roughly a 137-day growing season. To be safe most years, wait until Apr 25 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 24 | May 31 | May 12 |
| Freeze (32°F) | May 30 | May 10 | Apr 25 |
| Hard (28°F) | May 11 | Apr 25 | Apr 4 |
| Severe (24°F) | Apr 25 | Mar 31 | Mar 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 24 | Jun 15 | Jun 8 | Jun 3 | May 31 | May 27 | May 22 | May 18 | May 12 |
| 32°F | May 30 | May 22 | May 17 | May 13 | May 10 | May 7 | May 3 | Apr 30 | Apr 25 |
| 28°F | May 11 | May 5 | May 2 | Apr 29 | Apr 25 | Apr 22 | Apr 18 | Apr 13 | Apr 4 |
| 24°F | Apr 25 | Apr 17 | Apr 11 | Apr 4 | Mar 31 | Mar 28 | Mar 22 | Mar 16 | Mar 9 |
| 20°F | Apr 1 | Mar 24 | Mar 17 | Mar 13 | Mar 9 | Mar 6 | Mar 2 | Feb 27 | Feb 20 |
| 16°F | Mar 13 | Mar 8 | Mar 4 | Mar 1 | Feb 27 | Feb 23 | Feb 19 | Feb 13 | Feb 4 |
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) | Aug 29 | Sep 12 | Sep 27 |
| Freeze (32°F) | Sep 11 | Sep 26 | Oct 8 |
| Hard (28°F) | Sep 25 | Oct 7 | Oct 23 |
| Severe (24°F) | Oct 4 | Oct 20 | Nov 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 29 | Sep 3 | Sep 6 | Sep 9 | Sep 12 | Sep 15 | Sep 19 | Sep 22 | Sep 27 |
| 32°F | Sep 11 | Sep 16 | Sep 19 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 8 |
| 28°F | Sep 25 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 17 | Oct 23 |
| 24°F | Oct 4 | Oct 9 | Oct 13 | Oct 17 | Oct 20 | Oct 23 | Oct 28 | Nov 1 | Nov 7 |
| 20°F | Oct 15 | Oct 21 | Oct 25 | Oct 29 | Nov 2 | Nov 7 | Nov 12 | Nov 19 | Nov 26 |
| 16°F | Oct 24 | Oct 31 | Nov 5 | Nov 11 | Nov 16 | Nov 21 | Nov 26 | Dec 1 | Dec 10 |
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: Spokane Wfo, Wa, about 9.6 miles away@if(!empty($station['elevation_ft'])), at 2,392 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 Reardan, WA?
On average, the last spring frost (32°F) around Reardan, WA is about May 10. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 25.
When is the first frost in the fall?
The first fall frost around Reardan, WA typically arrives about Sep 26. 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 10 on average, or Apr 25 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 137 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 99029 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026