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 geography
Alaska counties on the map.
Each polygon is a county. Click for full frost-date detail. Color shows last-spring-frost timing — sage = earliest, amber = latest.
MapList
Last spring frostEarliestMedianLatest
29 counties · click any county for full frost data