Plant By Frost

Iowa

Frost dates for Forest City 2 Nne, IA

At this NOAA station the last spring frost (32°F) usually comes by April 30 and the first fall frost around October 7, giving a growing season of about 159 days.

April 30average last spring frost
October 7average first fall frost
JanAprJulOctDec

Frost odds

1 year in 10 the last spring frost is later thanMay 10
Half of years the last spring frost is later thanApril 30
9 years in 10 the last spring frost is later thanApril 14
1 year in 10 the first fall frost is earlier thanSeptember 22
Half of years the first fall frost is earlier thanOctober 7
9 years in 10 the first fall frost is earlier thanOctober 20

A hard freeze (28°F) usually ends by April 18 and returns around October 18.

A light frost (36°F, which can still nip tender plants) usually ends by May 8 and returns around September 28.

Station USC00132977, elevation 390 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