Frost dates for Campo Asos, CA
At Campo Asos, the median last spring frost (32°F) is Apr 29 and the median first fall frost is Nov 1, for a typical growing season of 184 days. For a 90% chance that the last frost has passed, wait until Jun 1. Nearby ZIP codes are in USDA hardiness zones 9a to 9b.
- Apr 29Last spring frost (median)50% chance of 32°F after this date
- Jun 1Safer planting date10% chance of 32°F after this date
- Nov 1First fall frost (median)50% chance of 32°F by this date
- 184 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 | May 2 | May 31 | Jun 23 |
| 32°F | Apr 7 | Apr 29 | Jun 1 |
| 28°F | Feb 23 | Mar 31 | Apr 26 |
| 24°F | Dec 24 | Feb 13 | Mar 24 |
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 | Sep 12 | Oct 8 | Nov 1 |
| 32°F | Oct 5 | Nov 1 | Nov 23 |
| 28°F | Oct 29 | Nov 27 | Dec 18 |
| 24°F | Nov 25 | Dec 16 | Feb 2 |
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 | 99 days | 132 days | 168 days |
| 32°F | 147 days | 184 days | 217 days |
| 28°F | 201 days | 240 days | 283 days |
| 24°F | 264 days | 310 days | 362 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 92% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 91905 | 9a | 20 to 25°F | 16 km |
| 91934 | 9b | 25 to 30°F | 30 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 USW00003164, at 32.6261, -116.4681, elevation 805 m (2,641 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 68.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Campo (0 km)
- Mount Laguna #3 (27 km)
- Alpine (37 km)
- Cuyamaca (42 km)
- El Capitan Dam (43 km)
- El Cajon (47 km)
- San Diego Brown Field (48 km)
- Julian Cdf (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.