Frost dates for Two Rivers, AK
At Two Rivers, the median last spring frost (32°F) is May 30 and the median first fall frost is Sep 2, for a typical growing season of 95 days. For a 90% chance that the last frost has passed, wait until Jun 13. Nearby ZIP codes are in USDA hardiness zone 3b.
- May 30Last spring frost (median)50% chance of 32°F after this date
- Jun 13Safer planting date10% chance of 32°F after this date
- Sep 2First fall frost (median)50% chance of 32°F by this date
- 95 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 12 | May 30 | Jun 13 |
| 28°F | Apr 30 | May 16 | May 31 |
| 24°F | Apr 17 | May 4 | May 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 |
|---|---|---|---|
| 32°F | Aug 13 | Sep 2 | Sep 17 |
| 28°F | Aug 31 | Sep 16 | Sep 30 |
| 24°F | Sep 10 | Sep 28 | Oct 11 |
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 | 43 days | 68 days | 90 days |
| 32°F | 70 days | 95 days | 117 days |
| 28°F | 99 days | 123 days | 145 days |
| 24°F | 121 days | 146 days | 168 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 |
|---|---|---|---|
| 99712 | 3b | -35 to -30°F | 53 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 USC00509489, at 64.8656, -146.9542, elevation 184 m (605 ft).
- Data quality: Representative (10+ years), 16 years of freeze data.
- Average days per year at or below 32°F: 236.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- N Pole (21 km)
- N Pole 1n (22 km)
- Eielson Field (23 km)
- Fort Knox Mine (24 km)
- Fairbanks 11 NE (29 km)
- Gilmore Creek (29 km)
- Fox 2 SE (33 km)
- Aurora (36 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.