Frost dates for Bethel Airport, AK
At Bethel Airport, the median last spring frost (32°F) is May 21 and the median first fall frost is Sep 22, for a typical growing season of 122 days. For a 90% chance that the last frost has passed, wait until Jun 2. Nearby ZIP codes are in USDA hardiness zones 3a to 5a.
- May 21Last spring frost (median)50% chance of 32°F after this date
- Jun 2Safer planting date10% chance of 32°F after this date
- Sep 22First fall frost (median)50% chance of 32°F by this date
- 122 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 20 | Jun 2 | Jun 14 |
| 32°F | May 8 | May 21 | Jun 2 |
| 28°F | Apr 30 | May 11 | May 26 |
| 24°F | Apr 21 | May 3 | May 18 |
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 23 | Sep 8 | Sep 22 |
| 32°F | Sep 7 | Sep 22 | Oct 4 |
| 28°F | Sep 19 | Oct 1 | Oct 15 |
| 24°F | Sep 29 | Oct 10 | Oct 23 |
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 | 74 days | 97 days | 116 days |
| 32°F | 104 days | 122 days | 140 days |
| 28°F | 124 days | 143 days | 161 days |
| 24°F | 141 days | 161 days | 180 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 |
|---|---|---|---|
| 99559 | 4a | -30 to -25°F | 3 km |
| 99634 | 4a | -30 to -25°F | 15 km |
| 99621 | 4a | -30 to -25°F | 22 km |
| 99551 | 3b | -35 to -30°F | 28 km |
| 99641 | 4a | -30 to -25°F | 36 km |
| 99552 | 3b | -35 to -30°F | 36 km |
| 99609 | 4a | -30 to -25°F | 39 km |
| 99679 | 3b | -35 to -30°F | 60 km |
| 99578 | 4a | -30 to -25°F | 64 km |
| 99680 | 4a | -30 to -25°F | 67 km |
| 99626 | 3b | -35 to -30°F | 113 km |
| 99657 | 3b | -35 to -30°F | 113 km |
| 99607 | 3b | -35 to -30°F | 115 km |
| 99655 | 4b | -25 to -20°F | 116 km |
| 99585 | 3b | -35 to -30°F | 121 km |
| 99622 | 4a | -30 to -25°F | 125 km |
| 99650 | 4a | -30 to -25°F | 140 km |
| 99561 | 4a | -30 to -25°F | 150 km |
| 99614 | 4a | -30 to -25°F | 156 km |
| 99658 | 4a | -30 to -25°F | 164 km |
| 99690 | 4a | -30 to -25°F | 168 km |
| 99589 | 4b | -25 to -20°F | 173 km |
| 99632 | 4a | -30 to -25°F | 177 km |
| 99681 | 4a | -30 to -25°F | 181 km |
| 99637 | 4a | -30 to -25°F | 181 km |
| 99678 | 4b | -25 to -20°F | 185 km |
| 99602 | 3a | -40 to -35°F | 188 km |
| 99651 | 4b | -25 to -20°F | 204 km |
| 99563 | 4a | -30 to -25°F | 207 km |
| 99662 | 4b | -25 to -20°F | 232 km |
| 99604 | 4b | -25 to -20°F | 243 km |
| 99630 | 5a | -20 to -15°F | 247 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 USW00026615, at 60.7850, -161.8292, elevation 31 m (102 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 214.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- King Salmon (374 km)
- Iliamna Airport (398 km)
- McGrath Airport (405 km)
- Port Alsworth (416 km)
- Port Alsworth 1 SW (416 km)
- Kaltag Airport (424 km)
- Intricate Bay (428 km)
- King Salmon 42 SE (439 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.