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.
Season in Days
|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.
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 May 4, 2005. The information contained within may not be the most current and accurate depending on when it is accessed.