Last spring frost
Apr 6
Frost Dates for Richland, WA
First fall frost
Oct 24
Growing season
200 days
Hardiness zone
7b
In an average year around Richland, WA, the last spring frost (32°F) is about Apr 6 and the first fall frost is about Oct 24, giving roughly a 200-day growing season. To be safe most years, wait until Mar 22 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 8 | Apr 25 | Apr 11 |
| Freeze (32°F) | Apr 24 | Apr 6 | Mar 22 |
| Hard (28°F) | Apr 5 | Mar 18 | Mar 1 |
| Severe (24°F) | Mar 18 | Feb 28 | Feb 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 8 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 22 | Apr 18 | Apr 15 | Apr 11 |
| 32°F | Apr 24 | Apr 17 | Apr 13 | Apr 10 | Apr 6 | Apr 3 | Mar 31 | Mar 28 | Mar 22 |
| 28°F | Apr 5 | Mar 31 | Mar 27 | Mar 23 | Mar 18 | Mar 14 | Mar 11 | Mar 6 | Mar 1 |
| 24°F | Mar 18 | Mar 11 | Mar 7 | Mar 3 | Feb 28 | Feb 26 | Feb 23 | Feb 17 | Feb 8 |
| 20°F | Mar 6 | Feb 28 | Feb 24 | Feb 19 | Feb 14 | Feb 7 | Jan 31 | Jan 18 | Jan 6 |
| 16°F | Feb 27 | Feb 18 | Feb 10 | Feb 1 | Jan 24 | Jan 15 | Jan 7 | Jan 1 | Dec 17 |
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 30 | Oct 14 | Oct 27 |
| Freeze (32°F) | Oct 10 | Oct 24 | Nov 8 |
| Hard (28°F) | Oct 20 | Nov 4 | Nov 23 |
| Severe (24°F) | Oct 29 | Nov 16 | Dec 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 5 | Oct 7 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
| 32°F | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 26 | Oct 30 | Nov 3 | Nov 8 |
| 28°F | Oct 20 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 16 | Nov 23 |
| 24°F | Oct 29 | Nov 3 | Nov 8 | Nov 12 | Nov 16 | Nov 21 | Nov 25 | Dec 1 | Dec 9 |
| 20°F | Nov 8 | Nov 15 | Nov 23 | Nov 28 | Dec 3 | Dec 7 | Dec 13 | Dec 22 | Jan 1 |
| 16°F | Nov 17 | Nov 27 | Dec 4 | Dec 9 | Dec 14 | Dec 20 | Dec 28 | Jan 4 | Jan 19 |
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: Richland, Wa, about 2.1 miles away@if(!empty($station['elevation_ft'])), at 373 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 Richland, WA?
On average, the last spring frost (32°F) around Richland, WA is about Apr 6. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 22.
When is the first frost in the fall?
The first fall frost around Richland, WA typically arrives about Oct 24. 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 6 on average, or Mar 22 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 200 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 99354 Planting calendar → Washington frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026