Plant By Frost

Alaska

Frost dates for Sitka Airport, AK

At this NOAA station the last spring frost (32°F) usually comes by April 12 and the first fall frost around November 1, giving a growing season of about 201 days.

April 12average last spring frost
November 1average first fall frost
JanAprJulOctDec

Frost odds

1 year in 10 the last spring frost is later thanApril 30
Half of years the last spring frost is later thanApril 12
9 years in 10 the last spring frost is later thanMarch 28
1 year in 10 the first fall frost is earlier thanOctober 13
Half of years the first fall frost is earlier thanNovember 1
9 years in 10 the first fall frost is earlier thanNovember 21

A hard freeze (28°F) usually ends by March 24 and returns around November 22.

A light frost (36°F, which can still nip tender plants) usually ends by May 2 and returns around October 15.

Station USW00025333, elevation 4 m. Based on 28 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