Frost dates for Gustavus, AK
At Gustavus, the median last spring frost (32°F) is May 30 and the median first fall frost is Sep 16, for a typical growing season of 107 days. For a 90% chance that the last frost has passed, wait until Jun 22. Nearby ZIP codes are in USDA hardiness zone 7a.
- May 30Last spring frost (median)50% chance of 32°F after this date
- Jun 22Safer planting date10% chance of 32°F after this date
- Sep 16First fall frost (median)50% chance of 32°F by this date
- 107 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 | May 30 | Jun 22 |
| 28°F | Apr 27 | May 12 | May 27 |
| 24°F | Apr 6 | Apr 26 | May 11 |
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 29 | Sep 16 | Oct 4 |
| 28°F | Sep 13 | Oct 1 | Oct 18 |
| 24°F | Oct 1 | Oct 17 | Nov 7 |
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 | 40 days | 70 days | 99 days |
| 32°F | 76 days | 107 days | 132 days |
| 28°F | 117 days | 142 days | 164 days |
| 24°F | 151 days | 174 days | 201 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 |
|---|---|---|---|
| 99826 | 7a | 0 to 5°F | 6 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 USW00025322, at 58.4111, -135.7089, elevation 12 m (40 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 161.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Gustavus 2 NE (2 km)
- Glacier Bay (11 km)
- Hoonah (38 km)
- Elfin Cove (44 km)
- Juneau Lena Point (55 km)
- Juneau Mile 17 (56 km)
- Pelican (59 km)
- Auke Bay (62 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.