Frost Dates in Iowa

The following chart is based on weather data collected from 1981 to 2010.* Probabilities indicate the likelihood of experiencing 32°F on or after the given date in spring and on or before the given date in fall.Oak with frost on leaves

Find your city or city closest to you to determine the likely date for the first freeze in fall and the last freeze in spring. 
Cities and towns listed are grouped by their location in the state from north to south. Within each group, cities are listed from west to east.

Date of First Freeze in Fall and Last Freeze in Spring


Northern Iowa Cities | North-Central Iowa Cities | South-Central Iowa Cities | Southern Iowa Cities


Northern Iowa

Location Date of first 32°F freeze in 10% of years Date of first 32°F freeze in 50% of years Date of first 32°F freeze in 90% of years Date of last 32°F freeze in 10% of years Date of last 32°F freeze in 50% of years Date of last 32°F freeze in 90% of years

Sioux Center

Sep. 19

Sep. 28

Oct. 8

Apr. 14

Apr. 28

May 14

Cherokee

Sep. 19

Sep. 26

Oct. 10

Apr. 18

May 1

May 16

Spirit Lake

Sep. 21

Oct. 3

Oct. 14

Apr. 8

Apr. 30

May 8

Mason City

Sep. 20

Oct. 3

Oct. 10

Apr. 19

May 3

May 16

New Hampton

Sep. 20

Oct. 2

Oct. 12

Apr. 10

Apr. 29

May 9

Fayette

Sep. 18

Sep. 29

Oct. 11

Apr. 17

May 6

May 21

Decorah

Sep. 21

Oct. 3

Oct. 13

Apr. 20

May 9

May 21

North-Central Iowa

Location Date of first 32°F freeze in 10% of years Date of first 32°F freeze in 50% of years Date of first 32°F freeze in 90% of years Date of last 32°F freeze in 10% of years Date of last 32°F freeze in 50% of years Date of last 32°F freeze in 90% of years

Sioux City

Sep. 20

Sep. 29

Oct. 13

Apr. 10

Apr. 26

May 11

Onawa

Sep. 20

Oct. 1

Oct. 14

Apr. 15

Apr. 28

May 10

Sac City

Sep. 20

Oct. 4

Oct. 17

Apr. 10

Apr. 26

May 10

Carroll

Sep. 18

Oct. 2

Oct. 10

Apr. 13

Apr. 27

May 10

Webster City

Sep. 18

Sep. 29

Oct. 10

Apr. 19

May 4

May 16

Ames

Sep. 23

Oct. 6

Oct. 21

Apr. 9

Apr. 20

May 6

Eldora

Sep. 25

Oct. 5

Oct. 17

Apr. 10

Apr. 23

May 8

Waterloo

Sep. 19

Sep. 29

Oct. 11

Apr. 15

Apr. 25

May 15

Cedar Rapids

Sep. 22

Oct. 5

Oct. 16

Apr. 9

Apr. 22

May 6

Manchester

Sep. 21

Sep. 30

Oct. 11

Apr. 18

May 2

May 14

Dubuque

Sep. 22

Oct. 5

Oct. 21

Apr. 9

Apr. 24

May 7

South-Central Iowa

Location Date of first 32°F freeze in 10% of years Date of first 32°F freeze in 50% of years Date of first 32°F freeze in 90% of years Date of last 32°F freeze in 10% of years Date of last 32°F freeze in 50% of years Date of last 32°F freeze in 90% of years

Council Bluffs

Sep. 23

Oct. 6

Oct. 24

Apr. 8

Apr. 22

May 7

Harlan

Sep. 22

Oct. 5

Oct. 24

Apr. 10

Apr. 24

May 9

Greenfield

Sep. 21

Oct. 6

Oct. 25

Apr. 9

Apr. 24

May 3

Des Moines

Sep. 26

Oct. 10

Oct. 27

Apr. 5

Apr. 18

Apr. 30

Grinnell

Sep. 16

Sep. 27

Oct. 10

Apr. 18

May 5

May 16

Sigourney

Oct. 1

1Oct. 2

Oct. 28

Apr. 5

Apr. 19

May 4

Washington

Sep. 22

Oct. 10

Oct. 21

Apr. 5

Apr. 17

May 5

Iowa City

Sep. 29

Oct. 13

Oct. 23

Mar. 31

Apr. 17

May 4

Le Claire

Oct. 3

Oct. 17

Nov. 2

28-Mar

Apr. 13

Apr. 27

Clinton

Sep. 22

Oct. 7

Oct. 19

Apr. 6

Apr. 19

May 6

Southern Iowa

Location Date of first 32°F freeze in 10% of years Date of first 32°F freeze in 50% of years Date of first 32°F freeze in 90% of years Date of last 32°F freeze in 10% of years Date of last 32°F freeze in 50% of years Date of last 32°F freeze in 90% of years

Red Oak

Sep. 18

Oct. 4

Oct. 17

Apr. 10

Apr. 22

May 6

Beaconsfield

Sep. 23

Oct. 5

Oct. 27

Apr. 9

Apr. 20

May 2

Chariton

Sep. 20

Sep. 30

Oct. 14

Apr. 17

Apr. 30

May 17

Ottumwa

Sep. 25

Oct. 7

Oct. 28

Apr. 3

Apr. 17

May 3

Keosauqua

Sep. 21

Oct. 7

Oct. 21

Apr. 9

Apr. 18

May 3

Fairfield

Sep. 22

Oct. 10

Oct. 25

Apr. 5

Apr. 17

May 4

Mount Pleasant

Sep. 23

Oct. 11

Oct. 22

Apr. 5

Apr. 18

May 6

Fort Madison

Sep. 30

Oct. 19

Nov. 6

30-Mar

Apr. 8

Apr. 19

Burlington

Oct. 3

Oct. 18

Nov. 4

30-Mar

Apr. 14

May 1

More Information

* The data in this chart was provided by the Midwestern Regional Climate Center (MRCC).

View a Frost/Freeze Map

Interactive mapping tools that utilize temperatures from the last 30 years can be found from the MRCC Vegetation Impact Program
Select the "Freeze Climatology" link in the menu located on the left side of the page to get 30-year averages for 32°F freezes and 28°F freezes.

 

Last Reviewed: 
August, 2022

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on . The information contained within may not be the most current and accurate depending on when it is accessed.