Last spring frost
Feb 18
Frost Dates for Vacaville, CA
First fall frost
Nov 28
Growing season
283 days
Hardiness zone
9b
In an average year around Vacaville, CA, the last spring frost (32°F) is about Feb 18 and the first fall frost is about Nov 28, giving roughly a 283-day growing season. To be safe most years, wait until Jan 11 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) | Apr 19 | Mar 28 | Feb 26 |
| Freeze (32°F) | Mar 25 | Feb 18 | Jan 11 |
| Hard (28°F) | Feb 17 | Jan 15 | Dec 21 |
| Severe (24°F) | Jan 29 | Dec 31 | Dec 11 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 19 | Apr 13 | Apr 7 | Apr 2 | Mar 28 | Mar 20 | Mar 13 | Mar 8 | Feb 26 |
| 32°F | Mar 25 | Mar 10 | Mar 3 | Feb 26 | Feb 18 | Feb 10 | Feb 1 | Jan 25 | Jan 11 |
| 28°F | Feb 17 | Feb 3 | Jan 30 | Jan 22 | Jan 15 | Jan 8 | Jan 3 | Dec 29 | Dec 21 |
| 24°F | Jan 29 | Jan 19 | Jan 11 | Jan 4 | Dec 31 | Dec 29 | Dec 24 | Dec 19 | Dec 11 |
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 1 | Nov 13 | Nov 30 |
| Freeze (32°F) | Nov 12 | Nov 28 | Dec 18 |
| Hard (28°F) | Nov 24 | Dec 10 | Jan 11 |
| Severe (24°F) | Dec 3 | Dec 21 | Jan 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 30 |
| 32°F | Nov 12 | Nov 17 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 4 | Dec 9 | Dec 18 |
| 28°F | Nov 24 | Dec 1 | Dec 3 | Dec 6 | Dec 10 | Dec 15 | Dec 22 | Jan 1 | Jan 11 |
| 24°F | Dec 3 | Dec 8 | Dec 12 | Dec 16 | Dec 21 | Dec 27 | Dec 31 | Jan 3 | Jan 17 |
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: Vacaville Nut Tree Ap, Ca, about 3.7 miles away@if(!empty($station['elevation_ft'])), at 109 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 Vacaville, CA?
On average, the last spring frost (32°F) around Vacaville, CA is about Feb 18. In cooler years it can run later, so for a safer bet many gardeners wait until Jan 11.
When is the first frost in the fall?
The first fall frost around Vacaville, CA typically arrives about Nov 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 Feb 18 on average, or Jan 11 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 283 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 95687 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026