Last spring frost
May 28
Frost Dates for Chester, CA
First fall frost
Sep 28
Growing season
124 days
Hardiness zone
7a
In an average year around Chester, CA, the last spring frost (32°F) is about May 28 and the first fall frost is about Sep 28, giving roughly a 124-day growing season. To be safe most years, wait until May 7 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) | Jul 2 | Jun 15 | May 31 |
| Freeze (32°F) | Jun 13 | May 28 | May 7 |
| Hard (28°F) | May 24 | May 2 | Apr 17 |
| Severe (24°F) | May 3 | Apr 13 | Mar 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jul 2 | Jun 26 | Jun 21 | Jun 18 | Jun 15 | Jun 11 | Jun 8 | Jun 5 | May 31 |
| 32°F | Jun 13 | Jun 8 | Jun 4 | May 31 | May 28 | May 22 | May 18 | May 14 | May 7 |
| 28°F | May 24 | May 16 | May 10 | May 6 | May 2 | Apr 30 | Apr 27 | Apr 23 | Apr 17 |
| 24°F | May 3 | Apr 26 | Apr 20 | Apr 16 | Apr 13 | Apr 10 | Apr 6 | Apr 3 | Mar 28 |
| 20°F | Apr 15 | Apr 7 | Apr 3 | Mar 29 | Mar 24 | Mar 18 | Mar 14 | Mar 8 | Mar 2 |
| 16°F | Apr 1 | Mar 19 | Mar 13 | Mar 9 | Mar 5 | Mar 1 | Feb 26 | Feb 19 | Feb 10 |
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 27 | Sep 12 | Sep 26 |
| Freeze (32°F) | Sep 12 | Sep 28 | Oct 14 |
| Hard (28°F) | Oct 1 | Oct 18 | Nov 1 |
| Severe (24°F) | Oct 19 | Nov 2 | Nov 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 27 | Sep 2 | Sep 6 | Sep 9 | Sep 12 | Sep 15 | Sep 19 | Sep 21 | Sep 26 |
| 32°F | Sep 12 | Sep 17 | Sep 21 | Sep 25 | Sep 28 | Oct 1 | Oct 5 | Oct 8 | Oct 14 |
| 28°F | Oct 1 | Oct 7 | Oct 11 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 |
| 24°F | Oct 19 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 13 | Nov 17 |
| 20°F | Nov 1 | Nov 5 | Nov 10 | Nov 14 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 3 |
| 16°F | Nov 13 | Nov 18 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 21 |
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: Chester, Ca, about 1.1 miles away@if(!empty($station['elevation_ft'])), at 4,530 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 Chester, CA?
On average, the last spring frost (32°F) around Chester, CA is about May 28. In cooler years it can run later, so for a safer bet many gardeners wait until May 7.
When is the first frost in the fall?
The first fall frost around Chester, CA typically arrives about Sep 28. 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 28 on average, or May 7 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 124 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 96020 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026