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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Last and First Frost Dates in Iowa

This article was published originally on 5/4/2005
Byline: 
by Richard Jauron, Department of Horticulture

 

The following chart is based on weather data collected from 1971 to 2000.* 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. 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.

  Spring Fall Median Growing
Season in Days
Location 50% 10% 10% 50%
Sioux Center May 2 May 14 Sept. 19 Sept. 29 152
Spencer May 2 May 12 Sept. 21 Sept. 26 154
Algona May 2 May 12 Sept. 21 Oct. 2 158
Mason City May 2 May 14 Sept. 20 Oct. 2 155
New Hampton April 29 May 9 Sept. 23 Oct. 5 162
Decorah May 5 May 23 Sept. 22 Oct. 4 152
 
Sioux City April 27 May 10 Sept. 21 Oct. 4 160
Ida Grove May 1 May 15 Sept. 18 Oct. 2 153
Fort Dodge May 2 May 14 Sept. 21 Oct. 5 157
Iowa Falls May 3 May 10 Sept. 20 Oct. 3 156
Waterloo May 1 May 12 Sept. 20 Sept. 30 152
Manchester May 3 May 15 Sept. 21 Sept. 30 148
Dubuque April 25 May 9 Sept. 22 Oct. 6 164
 
Harlan April 30 May 12 Sept. 23 Oct. 6 161
Guthrie Center May 2 May 11 Sept. 21 Oct. 2 153
Des Moines April 21 May 2 Sept. 29 Oct. 11 176
Newton April 19 May 5 Sept. 27 Oct. 8 175
Williamsburg April 27 May 13 Sept. 24 Oct. 7 162
Iowa City April 14 April 28 Oct. 1 Oct. 13 182
Le Claire April 13 April 30 Oct. 4 Oct. 17 189
 
Red Oak April 30 May 12 Sept. 18 Oct. 3 158
Creston April 25 May 8 Sept. 21 Oct. 7 161
Osceola April 23 May 9 Sept. 22 Oct. 10 169
Ottumwa April 13 April 27 Oct. 2 Oct. 16 183
Mount Pleasant April 21 May 6 Sept. 23 Oct. 10 174
Keokuk April 8 April 19 Oct. 8 Oct. 22 198

* 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.

 



This article originally appeared in the 5/4/2005 issue.

 

Year of Publication: 
2005
Issue: 
IC-493(9) -- May 4, 2005
by Richard Jauron, Department of Horticulture

Related information: