Frost dates for Porterville, CA
At Porterville, the median last spring frost (32°F) is Jan 20 and the median first fall frost is Dec 13, for a typical growing season of 330 days. For a 90% chance that the last frost has passed, wait until Feb 22. Nearby ZIP codes are in USDA hardiness zones 8b to 9b.
- Jan 20Last spring frost (median)50% chance of 32°F after this date
- Feb 22Safer planting date10% chance of 32°F after this date
- Dec 13First fall frost (median)50% chance of 32°F by this date
- 330 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 25 | Feb 26 | Apr 7 |
| 32°F | Dec 25 | Jan 20 | Feb 22 |
| 28°F | Dec 13 | Dec 31 | Jan 22 |
| 24°F | Dec 9 | Dec 26 | Jan 10 |
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 10 | Nov 28 | Dec 14 |
| 32°F | Nov 26 | Dec 13 | Jan 6 |
| 28°F | Dec 4 | Dec 23 | Jan 13 |
| 24°F | Dec 8 | Dec 24 | Jan 8 |
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 | 230 days | 273 days | 312 days |
| 32°F | 289 days | 330 days | 361 days |
| 28°F | 336 days | 365 days | 365 days |
| 24°F | 362 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 91% |
| 28°F | 48% |
| 24°F | 11% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 93258 | 9b | 25 to 30°F | 12 km |
| 93270 | 9b | 25 to 30°F | 14 km |
| 93257 | 9b | 25 to 30°F | 15 km |
| 93208 | 8b | 15 to 20°F | 35 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 USC00047077, at 36.0678, -119.0200, elevation 120 m (393 ft).
- Data quality: Representative (10+ years), 11 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
- Lindsay (15 km)
- Lemon Cove (35 km)
- Visalia (38 km)
- Delano (40 km)
- Three Rivers Edison Ph 1 (46 km)
- Glennville (48 km)
- Ash Mountain (50 km)
- Corcoran Irrig Dist (51 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.