Plant By Frost

Washington

Frost dates for Pullman 2 Nw, WA

At this NOAA station the last spring frost (32°F) usually comes by May 6 and the first fall frost around September 29, giving a growing season of about 143 days.

May 6average last spring frost
September 29average first fall frost
JanAprJulOctDec

Frost odds

1 year in 10 the last spring frost is later thanMay 25
Half of years the last spring frost is later thanMay 6
9 years in 10 the last spring frost is later thanApril 22
1 year in 10 the first fall frost is earlier thanSeptember 9
Half of years the first fall frost is earlier thanSeptember 29
9 years in 10 the first fall frost is earlier thanOctober 15

A hard freeze (28°F) usually ends by April 19 and returns around October 12.

A light frost (36°F, which can still nip tender plants) usually ends by June 1 and returns around September 11.

Station USC00456789, elevation 767 m. Based on 29 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