Frost dates for San Luis Obispo Airport, CA
At San Luis Obispo Airport, the median last spring frost (32°F) is Jan 31 and the median first fall frost is Dec 11, for a typical growing season of 319 days. For a 90% chance that the last frost has passed, wait until Mar 7. Nearby ZIP codes are in USDA hardiness zone 9b.
- Jan 31Last spring frost (median)50% chance of 32°F after this date
- Mar 7Safer planting date10% chance of 32°F after this date
- Dec 11First fall frost (median)50% chance of 32°F by this date
- 319 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 6 | Mar 17 | Apr 16 |
| 32°F | Dec 23 | Jan 31 | Mar 7 |
| 28°F | Dec 11 | Jan 3 | Feb 1 |
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 3 | Nov 24 | Dec 11 |
| 32°F | Nov 20 | Dec 11 | Jan 13 |
| 28°F | Dec 4 | Dec 28 | Jan 26 |
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 | 215 days | 250 days | 295 days |
| 32°F | 273 days | 319 days | 357 days |
| 28°F | 335 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 | 100% |
| 32°F | 95% |
| 28°F | 44% |
| 24°F | 6% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 93401 | 9b | 25 to 30°F | 2 km |
| 93420 | 9b | 25 to 30°F | 16 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 USW00093206, at 35.2372, -120.6414, elevation 61 m (200 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 8.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- San Luis Obispo Poly (8 km)
- Pismo Beach (9 km)
- Morro Bay Fire Dept (23 km)
- Twitchell Dam (40 km)
- Santa Maria Public Airport (41 km)
- Paso Robles (44 km)
- Paso Robles Muni Airport (48 km)
- Lompoc (67 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.