Last spring frost
Mar 16
Frost Dates for Three Rivers, CA
First fall frost
Nov 26
Growing season
249 days
Hardiness zone
9b
In an average year around Three Rivers, CA, the last spring frost (32°F) is about Mar 16 and the first fall frost is about Nov 26, giving roughly a 249-day growing season. To be safe most years, wait until Feb 5 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 4 | Apr 13 | Mar 21 |
| Freeze (32°F) | Apr 14 | Mar 16 | Feb 5 |
| Hard (28°F) | Mar 18 | Jan 30 | Dec 24 |
| Severe (24°F) | Feb 7 | Jan 3 | Dec 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 4 | Apr 27 | Apr 21 | Apr 17 | Apr 13 | Apr 9 | Apr 5 | Mar 31 | Mar 21 |
| 32°F | Apr 14 | Apr 7 | Apr 1 | Mar 25 | Mar 16 | Mar 9 | Feb 28 | Feb 19 | Feb 5 |
| 28°F | Mar 18 | Feb 28 | Feb 15 | Feb 6 | Jan 30 | Jan 23 | Jan 14 | Jan 3 | Dec 24 |
| 24°F | Feb 7 | Jan 28 | Jan 19 | Jan 11 | Jan 3 | Dec 31 | Dec 24 | Dec 19 | 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) | Oct 21 | Nov 10 | Nov 25 |
| Freeze (32°F) | Nov 5 | Nov 26 | Dec 12 |
| Hard (28°F) | Nov 22 | Dec 11 | Jan 11 |
| Severe (24°F) | Dec 1 | Dec 26 | Jan 30 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 21 | Oct 29 | Nov 3 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 25 |
| 32°F | Nov 5 | Nov 13 | Nov 18 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 6 | Dec 12 |
| 28°F | Nov 22 | Nov 28 | Dec 2 | Dec 7 | Dec 11 | Dec 16 | Dec 20 | Dec 26 | Jan 11 |
| 24°F | Dec 1 | Dec 9 | Dec 14 | Dec 19 | Dec 26 | Jan 1 | Jan 6 | Jan 16 | Jan 30 |
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: Three Rivers Edison Ph 1, Ca, about 2.4 miles away@if(!empty($station['elevation_ft'])), at 1,140 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 Three Rivers, CA?
On average, the last spring frost (32°F) around Three Rivers, CA is about Mar 16. In cooler years it can run later, so for a safer bet many gardeners wait until Feb 5.
When is the first frost in the fall?
The first fall frost around Three Rivers, CA typically arrives about Nov 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 Mar 16 on average, or Feb 5 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 249 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 93237 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026