Frost dates for Callahan, CA
At Callahan, the median last spring frost (32°F) is May 20 and the median first fall frost is Oct 5, for a typical growing season of 135 days. For a 90% chance that the last frost has passed, wait until Jun 12. Nearby ZIP codes are in USDA hardiness zone 8a.
- May 20Last spring frost (median)50% chance of 32°F after this date
- Jun 12Safer planting date10% chance of 32°F after this date
- Oct 5First fall frost (median)50% chance of 32°F by this date
- 135 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 24 | Jun 11 | Jul 2 |
| 32°F | May 2 | May 20 | Jun 12 |
| 28°F | Apr 6 | Apr 28 | May 21 |
| 24°F | Feb 28 | Mar 31 | Apr 27 |
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 4 | Sep 17 | Oct 3 |
| 32°F | Sep 20 | Oct 5 | Oct 22 |
| 28°F | Oct 5 | Oct 22 | Nov 10 |
| 24°F | Oct 21 | Nov 7 | Nov 29 |
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 | 73 days | 96 days | 119 days |
| 32°F | 107 days | 135 days | 159 days |
| 28°F | 147 days | 176 days | 201 days |
| 24°F | 187 days | 217 days | 255 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 96014 | 8a | 10 to 15°F | 7 km |
| 96034 | 8a | 10 to 15°F | 22 km |
| 96037 | 8a | 10 to 15°F | 24 km |
| 96032 | 8a | 10 to 15°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 USC00041316, at 41.3378, -122.8247, elevation 940 m (3,085 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 148.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Cecilville (34 km)
- Mount Shasta (41 km)
- Mount Shasta (42 km)
- Yreka (43 km)
- Dunsmuir Trtmt Pl (49 km)
- Montague Siskiyou Co Airport (57 km)
- McCloud (58 km)
- Orleans (59 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.