Frost dates for Big Delta Airport, AK
At Big Delta Airport, the median last spring frost (32°F) is May 17 and the median first fall frost is Sep 7, for a typical growing season of 113 days. For a 90% chance that the last frost has passed, wait until May 31. Nearby ZIP codes are in USDA hardiness zones 2a to 3b.
- May 17Last spring frost (median)50% chance of 32°F after this date
- May 31Safer planting date10% chance of 32°F after this date
- Sep 7First fall frost (median)50% chance of 32°F by this date
- 113 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 15 | May 29 | Jun 9 |
| 32°F | May 3 | May 17 | May 31 |
| 28°F | Apr 23 | May 6 | May 24 |
| 24°F | Apr 14 | Apr 28 | May 12 |
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 | Aug 13 | Aug 27 | Sep 9 |
| 32°F | Aug 23 | Sep 7 | Sep 22 |
| 28°F | Sep 3 | Sep 20 | Oct 1 |
| 24°F | Sep 13 | Sep 27 | Oct 10 |
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 | 72 days | 91 days | 109 days |
| 32°F | 93 days | 113 days | 134 days |
| 28°F | 111 days | 134 days | 154 days |
| 24°F | 130 days | 152 days | 170 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 |
|---|---|---|---|
| 99706 | 3b | -35 to -30°F | 51 km |
| 99714 | 3b | -35 to -30°F | 58 km |
| 99737 | 3a | -40 to -35°F | 65 km |
| 99702 | 2a | -50 to -45°F | 97 km |
| 99705 | 2a | -50 to -45°F | 114 km |
| 99712 | 3b | -35 to -30°F | 119 km |
| 99703 | 2a | -50 to -45°F | 131 km |
| 99707 | 3b | -35 to -30°F | 132 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 USW00026415, at 63.9944, -145.7214, elevation 389 m (1,277 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 219.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Delta 5 NE (11 km)
- Delta 6 N (14 km)
- Whitestone Farms (20 km)
- Delta Junction 20 SE (30 km)
- Dry Creek (65 km)
- Eielson Field (100 km)
- Paxson (108 km)
- Glennallen 64 N (108 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.