Frost dates for Juneau Forecast Office, AK
At Juneau Forecast Office, the median last spring frost (32°F) is May 9 and the median first fall frost is Oct 4, for a typical growing season of 146 days. For a 90% chance that the last frost has passed, wait until May 24. Nearby ZIP codes are in USDA hardiness zones 5b to 7a.
- May 9Last spring frost (median)50% chance of 32°F after this date
- May 24Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 146 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 13 | May 27 | Jun 7 |
| 32°F | Apr 28 | May 9 | May 24 |
| 28°F | Apr 9 | Apr 24 | May 9 |
| 24°F | Mar 21 | Apr 6 | Apr 20 |
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 20 | Oct 3 |
| 32°F | Sep 20 | Oct 4 | Oct 22 |
| 28°F | Oct 3 | Oct 20 | Nov 9 |
| 24°F | Oct 16 | Nov 7 | 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 | 95 days | 114 days | 134 days |
| 32°F | 125 days | 146 days | 168 days |
| 28°F | 153 days | 176 days | 201 days |
| 24°F | 187 days | 212 days | 235 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 |
|---|---|---|---|
| 99824 | 7a | 0 to 5°F | 18 km |
| 99801 | 6a | -10 to -5°F | 23 km |
| 99850 | 7a | 0 to 5°F | 54 km |
| 99829 | 7a | 0 to 5°F | 60 km |
| 99826 | 7a | 0 to 5°F | 72 km |
| 99841 | 7a | 0 to 5°F | 74 km |
| 99832 | 7a | 0 to 5°F | 101 km |
| 99827 | 5b | -15 to -10°F | 106 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 USC00504103, at 58.4003, -134.5694, elevation 32 m (106 ft).
- Data quality: Estimated from nearby stations (2+ years), 8 years of freeze data.
- Average days per year at or below 32°F: 158.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Juneau Intl Airport (5 km)
- Auke Bay (5 km)
- Juneau Mile 17 (10 km)
- Juneau Lena Point (12 km)
- Eaglecrest Base (14 km)
- Juneau Dwtn (15 km)
- Annex Creek (29 km)
- Snettisham Power Plant (56 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.