Frost dates · Alaska
Alaska frost dates,
county by county.
Last spring frost and first fall frost probability data for all 30 counties in Alaska, computed from the NOAA 1991–2020 Climate Normals. Every county page surfaces the full probability table at three temperature thresholds plus crop-specific planting guidance.
Variation across Alaska
87 days separate the earliest and latest counties.
The median last spring frost in Ketchikan Gateway Borough is March 13 — 87 days earlier than North Slope Borough at June 8. Statewide averages aren't useful planting tools; pick your county below for the data that actually applies to your fields.
By frost timing
Counties sorted by last spring frost.
Latest at top, earliest at bottom. In most states this matches the north-to-south gradient.
- North Slope BoroughSpring Jun 8·Fall Sep 488-day seasonLimited station data
- Southeast Fairbanks Census AreaSpring May 28·Fall Aug 2892-day season
- Northwest Arctic BoroughSpring May 27·Fall Oct 3129-day seasonLimited station data
- Lake and Peninsula BoroughSpring May 23·Fall Sep 24124-day season
- Nome Census AreaSpring May 23·Fall Sep 19119-day season
- Copper River Census AreaSpring May 16·Fall Sep 17124-day season
- Yukon-Koyukuk Census AreaSpring May 16·Fall Sep 8115-day season
- Denali BoroughSpring May 13·Fall Sep 19129-day season
- Bethel Census AreaSpring May 11·Fall Oct 1143-day seasonLimited station data
- Kusilvak Census AreaSpring May 11·Fall Oct 1143-day seasonLimited station data
- Fairbanks North Star BoroughSpring May 10·Fall Sep 14127-day season
- Aleutians West Census AreaSpring May 9·Fall Oct 24168-day seasonLimited station data
- Aleutians East BoroughSpring May 8·Fall Oct 21166-day season
- Bristol Bay BoroughSpring May 8·Fall Sep 27142-day season
- Dillingham Census AreaSpring May 8·Fall Sep 27142-day seasonLimited station data
- Matanuska-Susitna BoroughSpring May 5·Fall Sep 28146-day season
- Anchorage MunicipalitySpring May 1·Fall Oct 1153-day season
- Yakutat City and BoroughSpring Apr 28·Fall Oct 12167-day season
- Kenai Peninsula BoroughSpring Apr 23·Fall Oct 19179-day season
- Hoonah-Angoon Census AreaSpring Apr 20·Fall Oct 28191-day season
- Kodiak Island BoroughSpring Apr 18·Fall Oct 17182-day seasonLimited station data
- Juneau City and BoroughSpring Apr 11·Fall Oct 31203-day season
- Petersburg BoroughSpring Apr 11·Fall Nov 1204-day season
- Chugach Census AreaSpring Apr 10·Fall Oct 27200-day season
- Prince of Wales-Hyder Census AreaSpring Apr 9·Fall Nov 5210-day season
- Haines BoroughSpring Apr 7·Fall Oct 29205-day season
- Sitka City and BoroughSpring Apr 7·Fall Nov 10217-day season
- Skagway MunicipalitySpring Apr 5·Fall Nov 2211-day season
- Wrangell City and BoroughSpring Mar 24·Fall Nov 18239-day season
- Ketchikan Gateway BoroughSpring Mar 13·Fall Nov 26258-day season
Alphabetical
All Alaska counties — A to Z.
- Aleutians East Borough
- Aleutians West Census Area
- Anchorage Municipality
- Bethel Census Area
- Bristol Bay Borough
- Chugach Census Area
- Copper River Census Area
- Denali Borough
- Dillingham Census Area
- Fairbanks North Star Borough
- Haines Borough
- Hoonah-Angoon Census Area
- Juneau City and Borough
- Kenai Peninsula Borough
- Ketchikan Gateway Borough
- Kodiak Island Borough
- Kusilvak Census Area
- Lake and Peninsula Borough
- Matanuska-Susitna Borough
- Nome Census Area
- North Slope Borough
- Northwest Arctic Borough
- Petersburg Borough
- Prince of Wales-Hyder Census Area
- Sitka City and Borough
- Skagway Municipality
- Southeast Fairbanks Census Area
- Wrangell City and Borough
- Yakutat City and Borough
- Yukon-Koyukuk Census Area