Frost dates for Redlands, CA
At Redlands, the median last spring frost (32°F) is Jan 27 and the median first fall frost is Dec 19, for a typical growing season of 329 days. For a 90% chance that the last frost has passed, wait until Feb 28. Nearby ZIP codes are in USDA hardiness zones 9b to 10a.
- Jan 27Last spring frost (median)50% chance of 32°F after this date
- Feb 28Safer planting date10% chance of 32°F after this date
- Dec 19First fall frost (median)50% chance of 32°F by this date
- 329 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 31 | Mar 2 | Apr 5 |
| 32°F | Dec 21 | Jan 27 | Feb 28 |
| 28°F | Dec 17 | Jan 7 | Feb 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 | Nov 17 | Dec 2 | Dec 19 |
| 32°F | Dec 1 | Dec 19 | Jan 26 |
| 28°F | Dec 13 | Jan 1 | Feb 13 |
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 | 235 days | 272 days | 306 days |
| 32°F | 292 days | 329 days | 365 days |
| 28°F | 340 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 | 88% |
| 28°F | 26% |
| 24°F | 0% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 92374 | 10a | 30 to 35°F | 4 km |
| 92373 | 9b | 25 to 30°F | 4 km |
| 92354 | 10a | 30 to 35°F | 5 km |
| 92408 | 10a | 30 to 35°F | 9 km |
| 92324 | 10a | 30 to 35°F | 9 km |
| 92557 | 9b | 25 to 30°F | 9 km |
| 92346 | 10a | 30 to 35°F | 10 km |
| 92410 | 10a | 30 to 35°F | 10 km |
| 92369 | 10a | 30 to 35°F | 12 km |
| 92401 | 10a | 30 to 35°F | 12 km |
| 92359 | 10a | 30 to 35°F | 12 km |
| 92320 | 9b | 25 to 30°F | 14 km |
| 92411 | 10a | 30 to 35°F | 15 km |
| 92555 | 9b | 25 to 30°F | 16 km |
| 92399 | 9b | 25 to 30°F | 17 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 USC00047306, at 34.0369, -117.1947, elevation 430 m (1,410 ft).
- Data quality: Representative (10+ years), 18 years of freeze data.
- Average days per year at or below 32°F: 3.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Riverside Citrus Exp. (17 km)
- Riverside Fire Station 3 (20 km)
- Lake Arrowhead (23 km)
- Riverside Muni Airport (24 km)
- San Jacinto (34 km)
- Big Bear Lake (34 km)
- Ontario Intl Airport (37 km)
- Chino Airport (41 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.