Frost dates for Anchorage Upper De Armoun, AK
At Anchorage Upper De Armoun, the median last spring frost (32°F) is May 7 and the median first fall frost is Sep 28, for a typical growing season of 143 days. For a 90% chance that the last frost has passed, wait until May 23. Nearby ZIP codes are in USDA hardiness zones 5a to 5b.
- May 7Last spring frost (median)50% chance of 32°F after this date
- May 23Safer planting date10% chance of 32°F after this date
- Sep 28First fall frost (median)50% chance of 32°F by this date
- 143 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 9 | May 24 | Jun 5 |
| 32°F | Apr 23 | May 7 | May 23 |
| 28°F | Apr 10 | Apr 24 | May 7 |
| 24°F | Apr 2 | Apr 12 | Apr 30 |
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 5 | Sep 19 | Sep 30 |
| 32°F | Sep 16 | Sep 28 | Oct 12 |
| 28°F | Sep 26 | Oct 8 | Oct 21 |
| 24°F | Oct 2 | Oct 17 | Oct 31 |
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 | 98 days | 116 days | 134 days |
| 32°F | 124 days | 143 days | 162 days |
| 28°F | 147 days | 166 days | 185 days |
| 24°F | 167 days | 186 days | 204 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 |
|---|---|---|---|
| 99516 | 5b | -15 to -10°F | 3 km |
| 99507 | 5a | -20 to -15°F | 6 km |
| 99515 | 5a | -20 to -15°F | 9 km |
| 99518 | 5a | -20 to -15°F | 11 km |
| 99504 | 5a | -20 to -15°F | 11 km |
| 99508 | 5a | -20 to -15°F | 12 km |
| 99501 | 5a | -20 to -15°F | 15 km |
| 99517 | 5b | -15 to -10°F | 15 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 USC00500281, at 61.1025, -149.7169, elevation 407 m (1,335 ft).
- Data quality: Representative (10+ years), 15 years of freeze data.
- Average days per year at or below 32°F: 188.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Glen Alps (1 km)
- Anchorage Rabbit Creek #2 (3 km)
- Campbell Creek Sci Center (8 km)
- Fort Richardson Water Plant (14 km)
- Anchorage Merrill Field (15 km)
- Anchorage Forecast Office (16 km)
- Anchorage Lake Hood Airport (16 km)
- Anchorage Intl Airport (18 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.