Frost dates for Sonora, CA
At Sonora, the median last spring frost (32°F) is Apr 9 and the median first fall frost is Nov 9, for a typical growing season of 213 days. For a 90% chance that the last frost has passed, wait until Apr 30. Nearby ZIP codes are in USDA hardiness zones 8b to 9b.
- Apr 9Last spring frost (median)50% chance of 32°F after this date
- Apr 30Safer planting date10% chance of 32°F after this date
- Nov 9First fall frost (median)50% chance of 32°F by this date
- 213 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 | Apr 11 | Apr 30 | May 19 |
| 32°F | Mar 15 | Apr 9 | Apr 30 |
| 28°F | Jan 31 | Mar 4 | Apr 8 |
| 24°F | Dec 23 | Jan 28 | Feb 28 |
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 | Oct 7 | Oct 25 | Nov 12 |
| 32°F | Oct 19 | Nov 9 | Nov 27 |
| 28°F | Nov 7 | Nov 27 | Dec 19 |
| 24°F | Nov 24 | Dec 15 | Jan 27 |
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 | 152 days | 178 days | 202 days |
| 32°F | 186 days | 213 days | 244 days |
| 28°F | 227 days | 264 days | 305 days |
| 24°F | 286 days | 325 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 89% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 95370 | 9a | 20 to 25°F | 4 km |
| 95372 | 8b | 15 to 20°F | 11 km |
| 95309 | 9b | 25 to 30°F | 11 km |
| 95327 | 9b | 25 to 30°F | 16 km |
| 95383 | 8b | 15 to 20°F | 19 km |
| 95346 | 8b | 15 to 20°F | 22 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 USC00048353, at 37.9672, -120.3872, elevation 510 m (1,675 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 66.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- New Melones Dam HQ (10 km)
- Groveland 2 (20 km)
- Calaveras Big Trees (35 km)
- Cherry Valley Dam (41 km)
- Camp Pardee (51 km)
- Hetch Hetchy (53 km)
- Yosemite Village 12 W (55 km)
- Sutter Hill Cdf (58 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.