Frost dates for Imperial, CA
At Imperial, the median last spring frost (32°F) is Jan 4 and the median first fall frost is Dec 26, for a typical growing season of 360 days. For a 90% chance that the last frost has passed, wait until Feb 7. Nearby ZIP codes are in USDA hardiness zones 9b to 10a.
- Jan 4Last spring frost (median)50% chance of 32°F after this date
- Feb 7Safer planting date10% chance of 32°F after this date
- Dec 26First fall frost (median)50% chance of 32°F by this date
- 360 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 | Dec 28 | Jan 24 | Feb 21 |
| 32°F | Dec 13 | Jan 4 | Feb 7 |
| 28°F | Dec 14 | Jan 4 | Feb 6 |
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 27 | Dec 14 | Jan 1 |
| 32°F | Dec 6 | Dec 26 | Jan 25 |
| 28°F | Dec 13 | Jan 1 | Feb 6 |
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 | 292 days | 326 days | 354 days |
| 32°F | 330 days | 360 days | 365 days |
| 28°F | 362 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 | 96% |
| 32°F | 61% |
| 28°F | 12% |
| 24°F | 0% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 92243 | 10a | 30 to 35°F | 9 km |
| 92273 | 10a | 30 to 35°F | 13 km |
| 92251 | 10a | 30 to 35°F | 14 km |
| 92249 | 10a | 30 to 35°F | 16 km |
| 92231 | 10a | 30 to 35°F | 18 km |
| 92281 | 9b | 25 to 30°F | 23 km |
| 92227 | 10a | 30 to 35°F | 27 km |
| 92233 | 9b | 25 to 30°F | 34 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 USC00044223, at 32.8489, -115.5667, elevation -20 m (-64 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 4.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Imperial Co Airport (2 km)
- El Centro 2 SSW (9 km)
- El Centro Naf (11 km)
- Brawley 2 SW (12 km)
- Ocotillo Wells 2w (66 km)
- Mount Laguna #3 (80 km)
- Campo Asos (88 km)
- Campo (88 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.