Plant By Frost

Wyoming

Frost dates for Guernsey Dam #2, WY

At this NOAA station the last spring frost (32°F) usually comes by May 11 and the first fall frost around October 3, giving a growing season of about 144 days.

May 11average last spring frost
October 3average 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 11
9 years in 10 the last spring frost is later thanApril 29
1 year in 10 the first fall frost is earlier thanSeptember 19
Half of years the first fall frost is earlier thanOctober 3
9 years in 10 the first fall frost is earlier thanOctober 15

A hard freeze (28°F) usually ends by April 30 and returns around October 13.

A light frost (36°F, which can still nip tender plants) usually ends by May 22 and returns around September 24.

Station USC00484126, elevation 1327 m. Based on 3 years of 1991 to 2020 records. A garden higher up, in a hollow or far from this station can freeze later in spring.

Check another ZIP

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