Last spring frost
Apr 23
Frost Dates for Ruth, CA
First fall frost
Oct 19
Growing season
179 days
Hardiness zone
8b
In an average year around Ruth, CA, the last spring frost (32°F) is about Apr 23 and the first fall frost is about Oct 19, giving roughly a 179-day growing season. To be safe most years, wait until Apr 4 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 4 | May 13 | Apr 26 |
| Freeze (32°F) | May 11 | Apr 23 | Apr 4 |
| Hard (28°F) | Apr 18 | Mar 29 | Feb 27 |
| Severe (24°F) | Mar 17 | Feb 18 | Dec 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 4 | May 30 | May 22 | May 18 | May 13 | May 8 | May 3 | Apr 30 | Apr 26 |
| 32°F | May 11 | May 3 | Apr 29 | Apr 26 | Apr 23 | Apr 19 | Apr 14 | Apr 10 | Apr 4 |
| 28°F | Apr 18 | Apr 11 | Apr 7 | Apr 2 | Mar 29 | Mar 23 | Mar 16 | Mar 9 | Feb 27 |
| 24°F | Mar 17 | Mar 8 | Feb 28 | Feb 24 | Feb 18 | Feb 10 | Jan 31 | Jan 21 | Dec 31 |
| 20°F | Feb 21 | Feb 8 | Jan 30 | Jan 19 | Jan 12 | Jan 2 | Dec 27 | Dec 18 | Dec 5 |
| 16°F | Jan 30 | Jan 20 | Jan 10 | Jan 2 | Dec 28 | Dec 19 | Dec 15 | Dec 8 | 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 21 | Oct 4 | Oct 23 |
| Freeze (32°F) | Oct 2 | Oct 19 | Nov 8 |
| Hard (28°F) | Oct 14 | Nov 3 | Nov 28 |
| Severe (24°F) | Oct 29 | Nov 25 | Dec 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 26 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 11 | Oct 15 | Oct 23 |
| 32°F | Oct 2 | Oct 6 | Oct 11 | Oct 15 | Oct 19 | Oct 23 | Oct 28 | Nov 2 | Nov 8 |
| 28°F | Oct 14 | Oct 20 | Oct 25 | Oct 31 | Nov 3 | Nov 6 | Nov 12 | Nov 20 | Nov 28 |
| 24°F | Oct 29 | Nov 5 | Nov 12 | Nov 19 | Nov 25 | Dec 1 | Dec 4 | Dec 13 | Dec 31 |
| 20°F | Nov 13 | Nov 26 | Dec 1 | Dec 7 | Dec 12 | Dec 20 | Dec 27 | Jan 3 | Jan 20 |
| 16°F | Dec 1 | Dec 5 | Dec 13 | Dec 17 | Dec 21 | Dec 31 | Jan 4 | Jan 12 | Jan 24 |
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: Covelo, Ca, about 19.4 miles away@if(!empty($station['elevation_ft'])), at 1,413 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 Ruth, CA?
On average, the last spring frost (32°F) around Ruth, CA is about Apr 23. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 4.
When is the first frost in the fall?
The first fall frost around Ruth, CA typically arrives about Oct 19. 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 23 on average, or Apr 4 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 179 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 95595 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026