Last spring frost
Apr 9
Frost Dates for East Sonora, CA
First fall frost
Nov 9
Growing season
213 days
Hardiness zone
9a
In an average year around East Sonora, CA, the last spring frost (32°F) is about Apr 9 and the first fall frost is about Nov 9, giving roughly a 213-day growing season. To be safe most years, wait until Mar 15 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 19 | Apr 30 | Apr 11 |
| Freeze (32°F) | Apr 30 | Apr 9 | Mar 15 |
| Hard (28°F) | Apr 8 | Mar 4 | Jan 31 |
| Severe (24°F) | Feb 28 | Jan 28 | Dec 23 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 19 | May 11 | May 6 | May 2 | Apr 30 | Apr 26 | Apr 22 | Apr 18 | Apr 11 |
| 32°F | Apr 30 | Apr 23 | Apr 18 | Apr 13 | Apr 9 | Apr 5 | Apr 1 | Mar 25 | Mar 15 |
| 28°F | Apr 8 | Mar 29 | Mar 18 | Mar 11 | Mar 4 | Feb 28 | Feb 23 | Feb 12 | Jan 31 |
| 24°F | Feb 28 | Feb 19 | Feb 9 | Feb 3 | Jan 28 | Jan 20 | Jan 9 | Jan 1 | Dec 23 |
| 20°F | Feb 1 | Jan 27 | Jan 17 | Jan 10 | Jan 5 | Dec 31 | Dec 28 | Dec 23 | Dec 15 |
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 7 | Oct 25 | Nov 12 |
| Freeze (32°F) | Oct 19 | Nov 9 | Nov 27 |
| Hard (28°F) | Nov 7 | Nov 27 | Dec 19 |
| Severe (24°F) | Nov 24 | Dec 15 | Jan 27 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 7 | Oct 14 | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 5 | Nov 12 |
| 32°F | Oct 19 | Oct 27 | Nov 1 | Nov 4 | Nov 9 | Nov 12 | Nov 17 | Nov 21 | Nov 27 |
| 28°F | Nov 7 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 9 | Dec 19 |
| 24°F | Nov 24 | Dec 1 | Dec 6 | Dec 11 | Dec 15 | Dec 22 | Jan 1 | Jan 8 | Jan 27 |
| 20°F | Dec 5 | Dec 14 | Dec 20 | Dec 25 | Dec 29 | Jan 1 | Jan 8 | Jan 14 | Jan 27 |
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: Sonora, Ca, about 2.4 miles away@if(!empty($station['elevation_ft'])), at 1,675 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 East Sonora, CA?
On average, the last spring frost (32°F) around East Sonora, CA is about Apr 9. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 15.
When is the first frost in the fall?
The first fall frost around East Sonora, CA typically arrives about Nov 9. 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 9 on average, or Mar 15 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 213 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 95370 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026