Frost Dates in Iowa

Encyclopedia Article

Oak with frost on leavesThe 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.

Find your city or city closest to you to determine the likely date for first freeze in fall and 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

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
Northern Iowa            

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

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

North-Central Iowa

   

 

   

 

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

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

South-Central Iowa

   

 

   

 

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

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

Southern Iowa

   

 

   

 

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

* The data in this chart was provided by the Midwestern Regional Climate Center. Additional climatological information for the above locations and other sites in Iowa can be found at their website.

 

Last Reviewed: 
October, 2021