Plant By Frost

Alaska

Frost dates for Big Delta Airport, AK

At this NOAA station the last spring frost (32°F) usually comes by May 17 and the first fall frost around September 7, giving a growing season of about 113 days.

May 17average last spring frost
September 7average first fall frost
JanAprJulOctDec

Frost odds

1 year in 10 the last spring frost is later thanMay 31
Half of years the last spring frost is later thanMay 17
9 years in 10 the last spring frost is later thanMay 3
1 year in 10 the first fall frost is earlier thanAugust 23
Half of years the first fall frost is earlier thanSeptember 7
9 years in 10 the first fall frost is earlier thanSeptember 22

A hard freeze (28°F) usually ends by May 6 and returns around September 20.

A light frost (36°F, which can still nip tender plants) usually ends by May 29 and returns around August 27.

Station USW00026415, elevation 389 m. Based on 25 years of 1991 to 2020 records. A garden higher up, in a hollow or far from this station can freeze later in spring.

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Sources

  1. U.S. Annual/Seasonal Climate Normals, 1991 to 2020 (freeze probability dates by station), NOAA National Centers for Environmental Information, checked 1 November 2026
  2. Annual/Seasonal Normals 1991 to 2020 documentation, NOAA National Centers for Environmental Information, checked 1 November 2026
  3. 2024 Gazetteer Files, ZIP Code Tabulation Areas, US Census Bureau, checked 1 November 2026