Last spring frost
Jan 31
Frost Dates for Modesto, CA
First fall frost
Dec 5
Growing season
312 days
Hardiness zone
9b
In an average year around Modesto, CA, the last spring frost (32°F) is about Jan 31 and the first fall frost is about Dec 5, giving roughly a 312-day growing season. To be safe most years, wait until Dec 31 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) | Mar 31 | Mar 1 | Feb 3 |
| Freeze (32°F) | Feb 25 | Jan 31 | Dec 31 |
| Hard (28°F) | Feb 6 | Jan 8 | Dec 16 |
| Severe (24°F) | Jan 22 | Jan 1 | Dec 13 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 31 | Mar 18 | Mar 11 | Mar 5 | Mar 1 | Feb 26 | Feb 22 | Feb 15 | Feb 3 |
| 32°F | Feb 25 | Feb 18 | Feb 10 | Feb 5 | Jan 31 | Jan 25 | Jan 18 | Jan 10 | Dec 31 |
| 28°F | Feb 6 | Jan 29 | Jan 21 | Jan 14 | Jan 8 | Jan 3 | Dec 31 | Dec 25 | Dec 16 |
| 24°F | Jan 22 | Jan 15 | Jan 10 | Jan 4 | Jan 1 | Dec 31 | Dec 27 | Dec 20 | Dec 13 |
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) | Nov 8 | Nov 22 | Dec 9 |
| Freeze (32°F) | Nov 20 | Dec 5 | Jan 6 |
| Hard (28°F) | Dec 1 | Dec 21 | Jan 20 |
| Severe (24°F) | Dec 5 | Dec 27 | Jan 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 22 | Nov 25 | Nov 28 | Dec 1 | Dec 9 |
| 32°F | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 10 | Dec 16 | Dec 23 | Jan 6 |
| 28°F | Dec 1 | Dec 5 | Dec 11 | Dec 16 | Dec 21 | Dec 28 | Jan 1 | Jan 8 | Jan 20 |
| 24°F | Dec 5 | Dec 13 | Dec 18 | Dec 23 | Dec 27 | Dec 31 | Jan 1 | Jan 9 | Jan 15 |
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: Modesto City Co Ap, Ca, about 4.5 miles away@if(!empty($station['elevation_ft'])), at 73 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 Modesto, CA?
On average, the last spring frost (32°F) around Modesto, CA is about Jan 31. In cooler years it can run later, so for a safer bet many gardeners wait until Dec 31.
When is the first frost in the fall?
The first fall frost around Modesto, CA typically arrives about Dec 5. 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 Jan 31 on average, or Dec 31 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 312 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 95350 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026