Frost dates for Alturas Muni Airport, CA
At Alturas Muni Airport, the median last spring frost (32°F) is Jun 3 and the median first fall frost is Sep 12, for a typical growing season of 97 days. For a 90% chance that the last frost has passed, wait until Jun 24. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Jun 3Last spring frost (median)50% chance of 32°F after this date
- Jun 24Safer planting date10% chance of 32°F after this date
- Sep 12First fall frost (median)50% chance of 32°F by this date
- 97 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 |
|---|---|---|---|
| 32°F | May 14 | Jun 3 | Jun 24 |
| 28°F | Apr 25 | May 11 | Jun 3 |
| 24°F | Apr 7 | Apr 25 | May 13 |
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 |
|---|---|---|---|
| 32°F | Aug 27 | Sep 12 | Sep 27 |
| 28°F | Sep 10 | Sep 25 | Oct 8 |
| 24°F | Sep 24 | Oct 8 | Oct 24 |
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 | 39 days | 63 days | 87 days |
| 32°F | 73 days | 97 days | 124 days |
| 28°F | 110 days | 136 days | 157 days |
| 24°F | 144 days | 167 days | 188 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 96101 | 6b | -5 to 0°F | 6 km |
| 96015 | 7a | 0 to 5°F | 26 km |
| 96116 | 6b | -5 to 0°F | 28 km |
| 96108 | 6b | -5 to 0°F | 36 km |
| 96104 | 6b | -5 to 0°F | 36 km |
| 96110 | 6b | -5 to 0°F | 46 km |
| 96115 | 6b | -5 to 0°F | 46 km |
| 96006 | 7a | 0 to 5°F | 46 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 USW00094299, at 41.4914, -120.5644, elevation 1334 m (4,375 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 196.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Alturas (2 km)
- Canby 3 SW (29 km)
- Cedarville (32 km)
- Jess Valley (33 km)
- Adin Ranger Station (46 km)
- Fort Bidwell (54 km)
- Lava Beds Nat Mon (81 km)
- Tulelake (92 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.