Frost dates for Snettisham Power Plant, AK
At Snettisham Power Plant, the median last spring frost (32°F) is May 5 and the median first fall frost is Oct 15, for a typical growing season of 162 days. For a 90% chance that the last frost has passed, wait until May 22. Nearby ZIP codes are in USDA hardiness zones 6a to 7a.
- May 5Last spring frost (median)50% chance of 32°F after this date
- May 22Safer planting date10% chance of 32°F after this date
- Oct 15First fall frost (median)50% chance of 32°F by this date
- 162 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 4 | May 21 | Jun 2 |
| 32°F | Apr 19 | May 5 | May 22 |
| 28°F | Apr 3 | Apr 18 | May 7 |
| 24°F | Mar 20 | Apr 5 | Apr 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 |
|---|---|---|---|
| 36°F | Sep 20 | Oct 2 | Oct 15 |
| 32°F | Sep 30 | Oct 15 | Oct 31 |
| 28°F | Oct 12 | Oct 28 | Nov 13 |
| 24°F | Oct 24 | Nov 9 | Nov 25 |
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 | 116 days | 135 days | 155 days |
| 32°F | 139 days | 162 days | 183 days |
| 28°F | 166 days | 190 days | 213 days |
| 24°F | 192 days | 215 days | 240 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 |
|---|---|---|---|
| 99801 | 6a | -10 to -5°F | 36 km |
| 99824 | 7a | 0 to 5°F | 41 km |
| 99820 | 7a | 0 to 5°F | 91 km |
| 99829 | 7a | 0 to 5°F | 93 km |
| 99841 | 7a | 0 to 5°F | 107 km |
| 99850 | 7a | 0 to 5°F | 109 km |
| 99826 | 7a | 0 to 5°F | 125 km |
| 99832 | 7a | 0 to 5°F | 139 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 USC00508584, at 58.1422, -133.7386, elevation 9 m (29 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 168.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Annex Creek (29 km)
- Juneau Dwtn (43 km)
- Eaglecrest Base (48 km)
- Juneau Intl Airport (54 km)
- Juneau Forecast Office (56 km)
- Auke Bay (59 km)
- Juneau Mile 17 (66 km)
- Juneau Lena Point (66 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.