Frost dates · Iowa
Iowa frost dates,
county by county.
Last spring frost and first fall frost probability data for all 99 counties in Iowa, computed from the NOAA 1991–2020 Climate Normals. Every county page surfaces the full probability table at three temperature thresholds plus crop-specific planting guidance.
Variation across Iowa
29 days separate the earliest and latest counties.
The median last spring frost in Des Moines County is March 31 — 29 days earlier than Howard County at April 29. Statewide averages aren't useful planting tools; pick your county below for the data that actually applies to your fields.
By frost timing
Counties sorted by last spring frost.
Latest at top, earliest at bottom. In most states this matches the north-to-south gradient.
- Howard CountySpring Apr 29·Fall Oct 11165-day season
- Clayton CountySpring Apr 27·Fall Oct 11167-day season
- Lucas CountySpring Apr 26·Fall Oct 16173-day season
- Benton CountySpring Apr 25·Fall Oct 12170-day season
- Fayette CountySpring Apr 25·Fall Oct 15173-day season
- Osceola CountySpring Apr 25·Fall Oct 13171-day season
- Cerro Gordo CountySpring Apr 24·Fall Oct 11170-day season
- Cherokee CountySpring Apr 24·Fall Oct 15174-day season
- Hamilton CountySpring Apr 24·Fall Oct 12171-day season
- Worth CountySpring Apr 24·Fall Oct 13172-day season
- Delaware CountySpring Apr 23·Fall Oct 15175-day season
- Guthrie CountySpring Apr 23·Fall Oct 15175-day season
- Poweshiek CountySpring Apr 23·Fall Oct 17177-day season
- Audubon CountySpring Apr 22·Fall Oct 14175-day season
- Cass CountySpring Apr 22·Fall Oct 12173-day season
- Clay CountySpring Apr 22·Fall Oct 14175-day season
- Emmet CountySpring Apr 22·Fall Oct 14175-day season
- Winneshiek CountySpring Apr 22·Fall Oct 17178-day season
- Allamakee CountySpring Apr 21·Fall Oct 22184-day season
- Dickinson CountySpring Apr 21·Fall Oct 17179-day season
- Floyd CountySpring Apr 21·Fall Oct 17179-day season
- Jones CountySpring Apr 21·Fall Oct 16178-day season
- Lyon CountySpring Apr 21·Fall Oct 16178-day season
- Sioux CountySpring Apr 21·Fall Oct 14176-day season
- Buchanan CountySpring Apr 20·Fall Oct 17180-day season
- Chickasaw CountySpring Apr 20·Fall Oct 15178-day season
- Kossuth CountySpring Apr 20·Fall Oct 18181-day season
- Madison CountySpring Apr 20·Fall Oct 15178-day season
- Plymouth CountySpring Apr 20·Fall Oct 16179-day season
- Decatur CountySpring Apr 19·Fall Oct 19183-day season
- Franklin CountySpring Apr 19·Fall Oct 20184-day season
- Grundy CountySpring Apr 19·Fall Oct 18182-day season
- Harrison CountySpring Apr 19·Fall Oct 19183-day season
- Sac CountySpring Apr 19·Fall Oct 17181-day season
- Tama CountySpring Apr 19·Fall Oct 20184-day season
- Woodbury CountySpring Apr 19·Fall Oct 18182-day season
- Wright CountySpring Apr 19·Fall Oct 19183-day season
- Bremer CountySpring Apr 18·Fall Oct 20185-day season
- Clarke CountySpring Apr 18·Fall Oct 20185-day season
- Hancock CountySpring Apr 18·Fall Oct 17182-day season
- Iowa CountySpring Apr 18·Fall Oct 19184-day season
- O'Brien CountySpring Apr 18·Fall Oct 21186-day season
- Winnebago CountySpring Apr 18·Fall Oct 18183-day season
- Appanoose CountySpring Apr 17·Fall Oct 24190-day season
- Crawford CountySpring Apr 17·Fall Oct 22188-day season
- Dubuque CountySpring Apr 17·Fall Oct 21187-day season
- Henry CountySpring Apr 17·Fall Oct 20186-day season
- Ida CountySpring Apr 17·Fall Oct 21187-day season
- Linn CountySpring Apr 17·Fall Oct 22188-day season
- Marshall CountySpring Apr 17·Fall Oct 18184-day season
- Mitchell CountySpring Apr 17·Fall Oct 20186-day season
- Shelby CountySpring Apr 17·Fall Oct 20186-day season
- Union CountySpring Apr 17·Fall Oct 23189-day season
- Washington CountySpring Apr 17·Fall Oct 22188-day season
- Webster CountySpring Apr 17·Fall Oct 19185-day season
- Adair CountySpring Apr 16·Fall Oct 23190-day season
- Adams CountySpring Apr 16·Fall Oct 23190-day season
- Black Hawk CountySpring Apr 16·Fall Oct 20187-day season
- Boone CountySpring Apr 16·Fall Oct 22189-day season
- Butler CountySpring Apr 16·Fall Oct 20187-day season
- Calhoun CountySpring Apr 16·Fall Oct 21188-day season
- Carroll CountySpring Apr 16·Fall Oct 21188-day season
- Dallas CountySpring Apr 16·Fall Oct 22189-day season
- Hardin CountySpring Apr 16·Fall Oct 21188-day season
- Humboldt CountySpring Apr 16·Fall Oct 23190-day season
- Palo Alto CountySpring Apr 16·Fall Oct 20187-day season
- Pocahontas CountySpring Apr 16·Fall Oct 17184-day season
- Buena Vista CountySpring Apr 15·Fall Oct 23191-day season
- Greene CountySpring Apr 15·Fall Oct 21189-day season
- Jefferson CountySpring Apr 15·Fall Oct 22190-day season
- Louisa CountySpring Apr 15·Fall Oct 21189-day season
- Monona CountySpring Apr 15·Fall Oct 23191-day season
- Montgomery CountySpring Apr 15·Fall Oct 23191-day season
- Pottawattamie CountySpring Apr 15·Fall Oct 25193-day season
- Clinton CountySpring Apr 14·Fall Oct 24193-day season
- Jackson CountySpring Apr 14·Fall Oct 24193-day season
- Page CountySpring Apr 14·Fall Oct 21190-day season
- Ringgold CountySpring Apr 14·Fall Oct 23192-day season
- Story CountySpring Apr 14·Fall Oct 23192-day season
- Taylor CountySpring Apr 14·Fall Oct 26195-day season
- Van Buren CountySpring Apr 14·Fall Oct 23192-day season
- Warren CountySpring Apr 14·Fall Oct 21190-day season
- Polk CountySpring Apr 13·Fall Oct 25195-day season
- Wapello CountySpring Apr 13·Fall Oct 24194-day season
- Cedar CountySpring Apr 12·Fall Oct 25196-day season
- Jasper CountySpring Apr 12·Fall Oct 26197-day season
- Keokuk CountySpring Apr 12·Fall Oct 24195-day season
- Mills CountySpring Apr 12·Fall Oct 21192-day season
- Monroe CountySpring Apr 12·Fall Oct 26197-day season
- Scott CountySpring Apr 12·Fall Oct 24195-day season
- Mahaska CountySpring Apr 11·Fall Oct 27199-day season
- Wayne CountySpring Apr 11·Fall Oct 27199-day season
- Marion CountySpring Apr 10·Fall Oct 29202-day season
- Fremont CountySpring Apr 9·Fall Oct 29203-day season
- Johnson CountySpring Apr 9·Fall Oct 28202-day season
- Lee CountySpring Apr 7·Fall Nov 1208-day season
- Muscatine CountySpring Apr 7·Fall Oct 31207-day season
- Davis CountySpring Apr 6·Fall Oct 31208-day season
- Des Moines CountySpring Mar 31·Fall Nov 7221-day season
Alphabetical
All Iowa counties — A to Z.
- Adair County
- Adams County
- Allamakee County
- Appanoose County
- Audubon County
- Benton County
- Black Hawk County
- Boone County
- Bremer County
- Buchanan County
- Buena Vista County
- Butler County
- Calhoun County
- Carroll County
- Cass County
- Cedar County
- Cerro Gordo County
- Cherokee County
- Chickasaw County
- Clarke County
- Clay County
- Clayton County
- Clinton County
- Crawford County
- Dallas County
- Davis County
- Decatur County
- Delaware County
- Des Moines County
- Dickinson County
- Dubuque County
- Emmet County
- Fayette County
- Floyd County
- Franklin County
- Fremont County
- Greene County
- Grundy County
- Guthrie County
- Hamilton County
- Hancock County
- Hardin County
- Harrison County
- Henry County
- Howard County
- Humboldt County
- Ida County
- Iowa County
- Jackson County
- Jasper County
- Jefferson County
- Johnson County
- Jones County
- Keokuk County
- Kossuth County
- Lee County
- Linn County
- Louisa County
- Lucas County
- Lyon County
- Madison County
- Mahaska County
- Marion County
- Marshall County
- Mills County
- Mitchell County
- Monona County
- Monroe County
- Montgomery County
- Muscatine County
- O'Brien County
- Osceola County
- Page County
- Palo Alto County
- Plymouth County
- Pocahontas County
- Polk County
- Pottawattamie County
- Poweshiek County
- Ringgold County
- Sac County
- Scott County
- Shelby County
- Sioux County
- Story County
- Tama County
- Taylor County
- Union County
- Van Buren County
- Wapello County
- Warren County
- Washington County
- Wayne County
- Webster County
- Winnebago County
- Winneshiek County
- Woodbury County
- Worth County
- Wright County