Frost dates for Healdsburg, CA
At Healdsburg, the median last spring frost (32°F) is Feb 15 and the median first fall frost is Dec 2, for a typical growing season of 292 days. For a 90% chance that the last frost has passed, wait until Mar 17. Nearby ZIP codes are in USDA hardiness zone 9b.
- Feb 15Last spring frost (median)50% chance of 32°F after this date
- Mar 17Safer planting date10% chance of 32°F after this date
- Dec 2First fall frost (median)50% chance of 32°F by this date
- 292 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 27 | Mar 29 | Apr 20 |
| 32°F | Jan 4 | Feb 15 | Mar 17 |
| 28°F | Dec 14 | Jan 7 | Feb 2 |
| 24°F | Dec 10 | Jan 1 | Jan 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 | Nov 1 | Nov 16 | Dec 2 |
| 32°F | Nov 14 | Dec 2 | Jan 1 |
| 28°F | Nov 28 | Dec 17 | Jan 12 |
| 24°F | Dec 4 | Dec 30 | Jan 25 |
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 | 206 days | 234 days | 269 days |
| 32°F | 254 days | 292 days | 334 days |
| 28°F | 320 days | 347 days | 365 days |
| 24°F | 348 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 99% |
| 28°F | 70% |
| 24°F | 22% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 95448 | 9b | 25 to 30°F | 2 km |
| 95471 | 9b | 25 to 30°F | 14 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 USC00043875, at 38.6294, -122.8664, elevation 54 m (177 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 13.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Santa Rosa Sonoma Co Airport (15 km)
- Graton (22 km)
- Cloverdale (23 km)
- Calistoga (23 km)
- Santa Rosa (23 km)
- Occidental (28 km)
- Fort Ross (35 km)
- Saint Helena (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.