Frost dates for Winters, CA
At Winters, the median last spring frost (32°F) is Feb 18 and the median first fall frost is Nov 30, for a typical growing season of 284 days. For a 90% chance that the last frost has passed, wait until Mar 14. Nearby ZIP codes are in USDA hardiness zone 9b.
- Feb 18Last spring frost (median)50% chance of 32°F after this date
- Mar 14Safer planting date10% chance of 32°F after this date
- Nov 30First fall frost (median)50% chance of 32°F by this date
- 284 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Feb 24 | Mar 18 | Apr 13 |
| 32°F | Jan 17 | Feb 18 | Mar 14 |
| 28°F | Dec 18 | Jan 14 | Feb 17 |
| 24°F | Dec 10 | Dec 31 | Jan 22 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Nov 2 | Nov 15 | Nov 29 |
| 32°F | Nov 15 | Nov 30 | Dec 18 |
| 28°F | Nov 28 | Dec 15 | Jan 12 |
| 24°F | Dec 4 | Dec 27 | Jan 16 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 211 days | 240 days | 271 days |
| 32°F | 253 days | 284 days | 322 days |
| 28°F | 302 days | 336 days | 365 days |
| 24°F | 341 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 87% |
| 24°F | 37% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 95694 | 9b | 25 to 30°F | 9 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00049742, at 38.5253, -121.9778, elevation 41 m (135 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 15.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Lake Solano (4 km)
- Markley Cove (13 km)
- Vacaville (14 km)
- Vacaville Nut Tree Airport (17 km)
- Davis 2 WSW Exp. Farm (18 km)
- Woodland 1 WNW (24 km)
- Fairfield (29 km)
- Napa State Hospital (37 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.