Frost dates for Hearst Castle, CA
At Hearst Castle, the median last spring frost (32°F) is Feb 13 and the median first fall frost is Feb 1, for a typical growing season of 365 days. For a 90% chance that the last frost has passed, wait until Mar 31. Nearby ZIP codes are in USDA hardiness zones 9a to 10a.
- Feb 13Last spring frost (median)50% chance of 32°F after this date
- Mar 31Safer planting date10% chance of 32°F after this date
- Feb 1First fall frost (median)50% chance of 32°F by this date
- 365 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 | Jan 21 | Mar 13 | Apr 24 |
| 32°F | Dec 29 | Feb 13 | Mar 31 |
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 26 | Dec 25 | Feb 20 |
| 32°F | Dec 16 | Feb 1 | Mar 20 |
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 | 242 days | 283 days | 349 days |
| 32°F | 306 days | 365 days | 365 days |
| 28°F | 365 days | 365 days | 365 days |
| 24°F | 365 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 94% |
| 32°F | 40% |
| 28°F | 3% |
| 24°F | 0% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 93452 | 10a | 30 to 35°F | 9 km |
| 93428 | 10a | 30 to 35°F | 16 km |
| 93426 | 9a | 20 to 25°F | 25 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 USC00043882, at 35.6842, -121.1683, elevation 465 m (1,526 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 1.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Paso Robles (44 km)
- Morro Bay Fire Dept (46 km)
- Paso Robles Muni Airport (49 km)
- King City (58 km)
- San Luis Obispo Poly (62 km)
- San Luis Obispo Airport (69 km)
- Priest Valley (70 km)
- Pismo Beach (73 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.