When is the First Frost in Iowa?

As the temperatures begin to cool, and the calendar turns to September, it is starting to come to light that the first frost of the season will be here anytime now. The first frost of the season in an average year occurs near the end of September into early October across Iowa.

Here are a few cities and their average first frost date in the state of Iowa:

When Is the First Freeze of the Season in Iowa?

Then, not long after the first frost, comes the first freeze. For it to be a freeze, temperatures have to be temperatures below 32 degrees Fahrenheit. Normally the first freeze widespread comes from mid to late October as shown in the chart below.

Iowa County	Average First Freeze Date
Adair	October 7
Adams	October 9
Allamakee	October 8
Appanoose	October 15
Audubon	October 4
Benton	October 6
Black Hawk	October 6
Boone	October 7
Bremer	October 6
Buchanan	October 4
Buena Vista	October 8
Butler	October 8
Calhoun	October 8
Carroll	October 5
Cass	October 6
Cedar	October 10
Cerro Gordo	October 6
Cherokee	October 3
Chickasaw	October 6
Clarke	October 11
Clay	October 6
Clayton	October 5
Clinton	October 15
Crawford	October 8
Dallas	October 7
Davis	October 17
Decatur	October 14
Delaware	October 5
Des Moines	October 19
Dickinson	October 6
Dubuque	October 10
Emmet	October 6
Fayette	October 3
Floyd	October 8
Franklin	October 6
Fremont	October 14
Greene	October 7
Grundy	October 7
Guthrie	October 5
Hamilton	October 6
Hancock	October 6
Hardin	October 8
Harrison	October 9
Henry	October 16
Howard	October 3
Humboldt	October 8
Ida	October 5
Iowa	October 8
Jackson	October 10
Jasper	October 10
Jefferson	October 14
Johnson	October 11
Jones	October 5
Keokuk	October 14
Kossuth	October 7
Lee	October 20
Linn	October 7
Louisa	October 16
Lucas	October 9
Lyon	October 2
Madison	October 8
Mahaska	October 12
Marion	October 12
Marshall	October 8
Mills	October 11
Mitchell	October 6
Monona	October 8
Monroe	October 14
Montgomery	October 9
Muscatine	October 15
O’Brien	October 5
Osceola	October 4
Page	October 11
Palo Alto	October 8
Plymouth	October 4
Pocahontas	October 7
Polk	October 11
Pottawattamie	October 9
Poweshiek	October 8
Ringgold	October 12
Sac	October 8
Scott	October 19
Shelby	October 7
Sioux	October 3
Story	October 9
Tama	October 6
Taylor	October 11
Union	October 11
Van Buren	October 16
Wapello	October 16
Warren	October 11
Washington	October 14
Wayne	October 13
Webster	October 8
Winnebago	October 6
Winneshiek	October 3
Woodbury	October 6
Worth	October 6
Wright	October 5

Data from the Applied Climate Information System (ACIS)

Enjoy the fall weather while it is here, as winter will be here before you know it, and that means the winter preparations around your house will be in full swing before too long.

What is a frost advisory?
A Frost Advisory means that temperatures are expected to fall into the mid 30s°F, which could lead to frost on vegetation. Frost advisories are only issued during the growing season. Cover any sensitive vegetation outdoors.

What is a freeze watch?
A Freeze Watch means that temperatures are expected to fall below 32°F within the next 12 to 48 hours. Freeze watches are only issued during the growing season. This cold air will likely kill any sensitive vegetation that is not brought indoors or protected.

What is a freeze warning?
A Freeze Warning means that temperatures are expected to fall below 32°F within the next 36 hours. Freeze warnings are only issued during the growing season. This cold air will likely kill any sensitive vegetation that is not brought indoors or protected.