Counties in Iowa by average annual temperature

Fremont County had the highest average annual temperature of 99 counties in 2020, at 52.4 °F. Howard County had the lowest, at 45.5 °F. The median was 49.5 °F and the figure for Iowa was 49.2 °F. Source: NOAA National Centers for Environmental Information.

Keep it in a collection in your library.
Highest52.4Fremont County
Lowest45.5Howard County
Median49.599 counties
Iowa49.2History

Map of counties, 2020

Adair County: 49.9 °FAdams County: 50.6 °FAllamakee County: 47.1 °FAppanoose County: 51.3 °FAudubon County: 49.4 °FBenton County: 48 °FBlack Hawk County: 48.5 °FBoone County: 49.7 °FBremer County: 47.7 °FBuchanan County: 47.2 °FBuena Vista County: 48 °FButler County: 47.9 °FCalhoun County: 48.9 °FCarroll County: 49.5 °FCass County: 50.3 °FCedar County: 49.5 °FCerro Gordo County: 46.9 °FCherokee County: 48.1 °FChickasaw County: 46.5 °FClarke County: 51.1 °FClay County: 47.5 °FClayton County: 47.4 °FClinton County: 50.7 °FCrawford County: 49.5 °FDallas County: 50.4 °FDavis County: 51.3 °FDecatur County: 51.5 °FDelaware County: 47.6 °FDes Moines County: 51.8 °FDickinson County: 46.6 °FDubuque County: 48.1 °FEmmet County: 46.2 °FFayette County: 46.6 °FFloyd County: 47 °FFranklin County: 47.7 °FFremont County: 52.4 °FGreene County: 49.5 °FGrundy County: 48.4 °FGuthrie County: 50 °FHamilton County: 48.1 °FHancock County: 46.9 °FHardin County: 48.4 °FHarrison County: 50.6 °FHenry County: 51 °FHoward County: 45.5 °FHumboldt County: 47.9 °FIda County: 48.8 °FIowa County: 49.8 °FJackson County: 49.7 °FJasper County: 50.2 °FJefferson County: 50.2 °FJohnson County: 49.6 °FJones County: 49.1 °FKeokuk County: 50.4 °FKossuth County: 47 °FLee County: 52.1 °FLinn County: 48.6 °FLouisa County: 51.5 °FLucas County: 51 °FLyon County: 47 °FMadison County: 50.5 °FMahaska County: 50.6 °FMarion County: 50.6 °FMarshall County: 49.2 °FMills County: 51.9 °FMitchell County: 46.1 °FMonona County: 49.9 °FMonroe County: 51.1 °FMontgomery County: 51.4 °FMuscatine County: 50.4 °FO'Brien County: 47.4 °FOsceola County: 46.4 °FPage County: 52.1 °FPalo Alto County: 47.2 °FPlymouth County: 48.7 °FPocahontas County: 47.8 °FPolk County: 50.5 °FPottawattamie County: 51 °FPoweshiek County: 49.9 °FRinggold County: 51.2 °FSac County: 49 °FScott County: 51.1 °FShelby County: 49.9 °FSioux County: 47.6 °FStory County: 49.5 °FTama County: 48.8 °FTaylor County: 51.4 °FUnion County: 50.5 °FVan Buren County: 50.9 °FWapello County: 50.9 °FWarren County: 51.1 °FWashington County: 50.5 °FWayne County: 51.1 °FWebster County: 48.4 °FWinnebago County: 46.2 °FWinneshiek County: 46.9 °FWoodbury County: 49.4 °FWorth County: 46 °FWright County: 47.4 °F
  • Under 47
  • 47 to 48
  • 48 to 50
  • 50 to 51
  • 51 and over
°F, 2020. Source: NOAA NCEI, NOAA Climate at a Glance, January to December average temperature, counties. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2020

Fremont County: 52.4 °FFremont County52.4Lee County: 52.1 °FLee County52.1Page County: 52.1 °FPage County52.1Mills County: 51.9 °FMills County51.9Des Moines County: 51.8 °FDes Moines County51.8Decatur County: 51.5 °FDecatur County51.5Louisa County: 51.5 °FLouisa County51.5Montgomery County: 51.4 °FMontgomery County51.4Taylor County: 51.4 °FTaylor County51.4Appanoose County: 51.3 °FAppanoose County51.3Davis County: 51.3 °FDavis County51.3Ringgold County: 51.2 °FRinggold County51.2Clarke County: 51.1 °FClarke County51.1Monroe County: 51.1 °FMonroe County51.1Scott County: 51.1 °FScott County51.1Warren County: 51.1 °FWarren County51.1Wayne County: 51.1 °FWayne County51.1Henry County: 51 °FHenry County51Lucas County: 51 °FLucas County51Pottawattamie County: 51 °FPottawattamie County51Van Buren County: 50.9 °FVan Buren County50.9Wapello County: 50.9 °FWapello County50.9Clinton County: 50.7 °FClinton County50.7Adams County: 50.6 °FAdams County50.6Harrison County: 50.6 °FHarrison County50.6Mahaska County: 50.6 °FMahaska County50.6Marion County: 50.6 °FMarion County50.6Madison County: 50.5 °FMadison County50.5Polk County: 50.5 °FPolk County50.5Union County: 50.5 °FUnion County50.5Washington County: 50.5 °FWashington County50.5Dallas County: 50.4 °FDallas County50.4Keokuk County: 50.4 °FKeokuk County50.4Muscatine County: 50.4 °FMuscatine County50.4Cass County: 50.3 °FCass County50.3Jasper County: 50.2 °FJasper County50.2Jefferson County: 50.2 °FJefferson County50.2Guthrie County: 50 °FGuthrie County50Adair County: 49.9 °FAdair County49.9Monona County: 49.9 °FMonona County49.9Fremont County: 52.4 °FFremont County52.4Lee County: 52.1 °FLee County52.1Page County: 52.1 °FPage County52.1Mills County: 51.9 °FMills County51.9Des Moines County: 51.8 °FDes Moines County51.8Decatur County: 51.5 °FDecatur County51.5Louisa County: 51.5 °FLouisa County51.5Montgomery County: 51.4 °FMontgomery County51.4Taylor County: 51.4 °FTaylor County51.4Appanoose County: 51.3 °FAppanoose County51.3Davis County: 51.3 °FDavis County51.3Ringgold County: 51.2 °FRinggold County51.2Clarke County: 51.1 °FClarke County51.1Monroe County: 51.1 °FMonroe County51.1Scott County: 51.1 °FScott County51.1Warren County: 51.1 °FWarren County51.1Wayne County: 51.1 °FWayne County51.1Henry County: 51 °FHenry County51Lucas County: 51 °FLucas County51Pottawattamie County: 51 °FPottawattamie County51Van Buren County: 50.9 °FVan Buren County50.9Wapello County: 50.9 °FWapello County50.9Clinton County: 50.7 °FClinton County50.7Adams County: 50.6 °FAdams County50.6Harrison County: 50.6 °FHarrison County50.6Mahaska County: 50.6 °FMahaska County50.6Marion County: 50.6 °FMarion County50.6Madison County: 50.5 °FMadison County50.5Polk County: 50.5 °FPolk County50.5Union County: 50.5 °FUnion County50.5Washington County: 50.5 °FWashington County50.5Dallas County: 50.4 °FDallas County50.4Keokuk County: 50.4 °FKeokuk County50.4Muscatine County: 50.4 °FMuscatine County50.4Cass County: 50.3 °FCass County50.3Jasper County: 50.2 °FJasper County50.2Jefferson County: 50.2 °FJefferson County50.2Guthrie County: 50 °FGuthrie County50Adair County: 49.9 °FAdair County49.9Monona County: 49.9 °FMonona County49.9
°F. Source: NOAA NCEI, NOAA Climate at a Glance, January to December average temperature, counties. Retrieved 2026-10-12.

Full ranking

RankCounties2020
°F
Change on 2019
1Fremont County52.4+4.6%
2Lee County52.1+3%
2Page County52.1+4.2%
4Mills County51.9+4.4%
5Des Moines County51.8+3.4%
6Decatur County51.5+3.4%
6Louisa County51.5+4.9%
8Montgomery County51.4+4.5%
8Taylor County51.4+4%
10Appanoose County51.3+3.4%
10Davis County51.3+2.6%
12Ringgold County51.2+3.4%
13Clarke County51.1+4.3%
13Monroe County51.1+3.7%
13Scott County51.1+4.9%
13Warren County51.1+4.5%
13Wayne County51.1+3.9%
18Henry County51+4.5%
18Lucas County51+4.1%
18Pottawattamie County51+4.5%
21Van Buren County50.9+3.2%
21Wapello County50.9+2.6%
23Clinton County50.7+4.5%
24Adams County50.6+4.5%
24Harrison County50.6+5.2%
24Mahaska County50.6+3.5%
24Marion County50.6+3.7%
28Madison County50.5+4.8%
28Polk County50.5+4.6%
28Union County50.5+4.3%
28Washington County50.5+3.9%
32Dallas County50.4+5%
32Keokuk County50.4+3.5%
32Muscatine County50.4+4.3%
35Cass County50.3+4.6%
36Jasper County50.2+4.6%
36Jefferson County50.2+3.3%
38Guthrie County50+5.3%
39Adair County49.9+4.8%
39Monona County49.9+5.5%
39Poweshiek County49.9+4.6%
39Shelby County49.9+5.3%
43Iowa County49.8+4.4%
44Boone County49.7+5.3%
44Jackson County49.7+4.2%
46Johnson County49.6+4%
47Carroll County49.5+5.5%
47Cedar County49.5+3.8%
47Crawford County49.5+5.5%
47Greene County49.5+5.1%
47Story County49.5+5.1%
52Audubon County49.4+5.3%
52Woodbury County49.4+6%
54Marshall County49.2+4.9%
55Jones County49.1+3.4%
56Sac County49+6.3%
57Calhoun County48.9+6.1%
58Ida County48.8+6.1%
58Tama County48.8+5.2%
60Plymouth County48.7+6.8%
61Linn County48.6+4.7%
62Black Hawk County48.5+5.9%
63Grundy County48.4+5.2%
63Hardin County48.4+5.2%
63Webster County48.4+5.7%
66Cherokee County48.1+7.1%
66Dubuque County48.1+3.9%
66Hamilton County48.1+5.3%
69Benton County48+5%
69Buena Vista County48+6.4%
71Butler County47.9+5.5%
71Humboldt County47.9+6%
73Pocahontas County47.8+6%
74Bremer County47.7+5.3%
74Franklin County47.7+5.5%
76Delaware County47.6+4.2%
76Sioux County47.6+7%
78Clay County47.5+6.5%
79Clayton County47.4+4.4%
79O'Brien County47.4+7.2%
79Wright County47.4+5.6%
82Buchanan County47.2+4.9%
82Palo Alto County47.2+5.8%
84Allamakee County47.1+4.7%
85Floyd County47+5.6%
85Kossuth County47+6.6%
85Lyon County47+7.1%
88Cerro Gordo County46.9+5.6%
88Hancock County46.9+5.9%
88Winneshiek County46.9+6.8%
91Dickinson County46.6+7.1%
91Fayette County46.6+5%
93Chickasaw County46.5+5.2%
94Osceola County46.4+7.4%
95Emmet County46.2+6.7%
95Winnebago County46.2+6.2%
97Mitchell County46.1+5.7%
98Worth County46+6%
99Howard County45.5+5.3%

Other periods

About this ranking

Mean air temperature from January to December, in degrees Fahrenheit: the average of the 12 monthly mean temperatures. NOAA computes it from its climate divisional dataset (nClimDiv): station readings interpolated onto a 5 km grid and averaged over the area.

Values are area averages, so a county with mountains and valleys has one value for very different local climates. NOAA revises the last two years every month.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December average temperature, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

NOAA National Centers for Environmental Information. (2026). NOAA Climate at a Glance, January to December average temperature, counties (Counties in Iowa by average annual temperature, 2020) [Data set]. Retrieved October 12, 2026, from https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping

MLA 9

NOAA Climate at a Glance, January to December average temperature, counties, Counties in Iowa by average annual temperature, 2020. NOAA National Centers for Environmental Information, 6 Oct. 2026, https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Invokely, https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

NOAA National Centers for Environmental Information. 2026. NOAA Climate at a Glance, January to December average temperature, counties. Counties in Iowa by average annual temperature, 2020. Dataset. Accessed October 12, 2026. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Also distributed by Invokely, https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020.

Harvard

NOAA National Centers for Environmental Information (2026) NOAA Climate at a Glance, January to December average temperature, counties, Counties in Iowa by average annual temperature, 2020 [Dataset]. Available at: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping, via Invokely: https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020 (Accessed: 12 October 2026).

BibTeX
@misc{noaa_counties_in_iowa_by_2020,
  author = {{NOAA National Centers for Environmental Information}},
  title = {{NOAA Climate at a Glance, January to December average temperature, counties: Counties in Iowa by average annual temperature, 2020}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020. Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December average temperature, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - NOAA National Centers for Environmental Information
TI  - NOAA Climate at a Glance, January to December average temperature, counties: Counties in Iowa by average annual temperature, 2020
PY  - 2026
DA  - 2026/10/06
PB  - NOAA National Centers for Environmental Information
DB  - Invokely
UR  - https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping
L2  - https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/average-annual-temperature/iowa-counties?period=2020.
N1  - Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December average temperature, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.
ER  - 
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Rank Counties in Iowa by average annual temperature using official data, and cite the source.
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Questions

Which county has the highest average annual temperature?

Fremont County, with 52.4 °F in 2020, according to NOAA National Centers for Environmental Information.

Which county has the lowest average annual temperature?

Howard County, with 45.5 °F in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: NOAA National Centers for Environmental Information, NOAA Climate at a Glance, January to December average temperature, counties. Retrieved 2026-10-12.

Average annual temperature: other rankings

Counties in Iowa: more rankings