Plant By Frost

Illinois

Frost dates for Rend Lake Dam, IL

At this NOAA station the last spring frost (32°F) usually comes by April 4 and the first fall frost around October 27, giving a growing season of about 204 days.

April 4average last spring frost
October 27average first fall frost
JanAprJulOctDec

Frost odds

1 year in 10 the last spring frost is later thanApril 19
Half of years the last spring frost is later thanApril 4
9 years in 10 the last spring frost is later thanMarch 21
1 year in 10 the first fall frost is earlier thanOctober 16
Half of years the first fall frost is earlier thanOctober 27
9 years in 10 the first fall frost is earlier thanNovember 8

A hard freeze (28°F) usually ends by March 26 and returns around November 5.

A light frost (36°F, which can still nip tender plants) usually ends by April 15 and returns around October 18.

Station USC00117187, elevation 139 m. Based on 8 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