Frost dates for Palomar Mountain Obsy, CA
At Palomar Mountain Obsy, the median last spring frost (32°F) is Apr 29 and the median first fall frost is Nov 18, for a typical growing season of 201 days. For a 90% chance that the last frost has passed, wait until May 29. Nearby ZIP codes are in USDA hardiness zones 8b to 9b.
- Apr 29Last spring frost (median)50% chance of 32°F after this date
- May 29Safer planting date10% chance of 32°F after this date
- Nov 18First fall frost (median)50% chance of 32°F by this date
- 201 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 23 | May 19 | Jun 7 |
| 32°F | Apr 2 | Apr 29 | May 29 |
| 28°F | Feb 26 | Apr 5 | May 5 |
| 24°F | Jan 6 | Mar 4 | Apr 15 |
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 10 | Nov 1 | Nov 21 |
| 32°F | Oct 27 | Nov 18 | Dec 8 |
| 28°F | Nov 10 | Dec 6 | Dec 31 |
| 24°F | Nov 30 | Dec 25 | Feb 19 |
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 | 137 days | 165 days | 201 days |
| 32°F | 164 days | 201 days | 236 days |
| 28°F | 201 days | 243 days | 285 days |
| 24°F | 248 days | 291 days | 351 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 95% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 92060 | 9a | 20 to 25°F | 4 km |
| 92061 | 9b | 25 to 30°F | 12 km |
| 92536 | 9b | 25 to 30°F | 13 km |
| 92539 | 8b | 15 to 20°F | 24 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 USC00046657, at 33.3781, -116.8400, elevation 1692 m (5,550 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 49.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Henshaw Dam (17 km)
- Valley Center 1n (25 km)
- Fallbrook 5 NE (33 km)
- San Pasqual Animal Pk (35 km)
- Escondido #2 (37 km)
- Ramona Airport (39 km)
- Vista (40 km)
- Hemet (40 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.