Heat Wave Risk in Iowa

All Iowa counties ranked by FEMA National Risk Index heat wave score

Heat Wave risk — prolonged periods of extreme heat that threaten health and infrastructure — is rated for 99 of 99 Iowa counties in FEMA's National Risk Index. Polk County carries the state's highest heat wave score at 96.7, with $11M in expected annual heat wave losses.

1 Iowa county is rated High or Very High for heat wave, and expected annual losses from heat wave total roughly $61M statewide. The full ranking below links to each county's complete 18-hazard risk profile.

County Rankings — Heat Wave

#CountyHeat Wave ScoreRatingAnn. Freq.Ann. Loss
1 Polk County
96.7
High 7.32 / yr $11M
2 Johnson County
87.5
Medium 7.00 / yr $4M
3 Scott County
86.9
Medium 7.21 / yr $3M
4 Page County
85.7
Medium 8.21 / yr $2M
5 Lee County
84.9
Medium 9.26 / yr $2M
6 Pottawattamie County
83.7
Medium 7.79 / yr $2M
7 Des Moines County
83.4
Medium 9.00 / yr $2M
8 Woodbury County
83.2
Medium 6.53 / yr $2M
9 Union County
82.7
Medium 7.68 / yr $1M
10 Taylor County
81.5
Medium 7.68 / yr $1M
11 Henry County
81.0
Medium 9.00 / yr $2M
12 Jefferson County
79.5
Medium 8.89 / yr $1M
13 Muscatine County
76.5
Low 7.26 / yr $1M
14 Davis County
75.7
Low 7.58 / yr $827K
15 Wapello County
75.1
Low 7.47 / yr $1M
16 Dallas County
74.7
Low 7.05 / yr $2M
17 Van Buren County
74.2
Low 9.16 / yr $865K
18 Cass County
71.8
Low 7.32 / yr $775K
19 Montgomery County
69.8
Low 8.00 / yr $933K
20 Appanoose County
69.5
Low 7.63 / yr $708K
21 Linn County
69.2
Low 5.95 / yr $1M
22 Warren County
65.5
Low 7.53 / yr $1M
23 Washington County
64.7
Low 8.26 / yr $716K
24 Decatur County
63.6
Low 7.74 / yr $660K
25 Ringgold County
63.2
Low 7.68 / yr $934K
26 Marion County
61.5
Low 7.16 / yr $798K
27 Dubuque County
61.0
Low 4.58 / yr $1M
28 Adair County
59.5
Low 7.32 / yr $502K
29 Lucas County
54.9
Low 7.58 / yr $385K
30 Mahaska County
54.9
Low 6.95 / yr $537K
31 Clarke County
54.3
Low 7.63 / yr $656K
32 Clinton County
54.2
Low 6.16 / yr $474K
33 Adams County
53.0
Low 7.63 / yr $468K
34 Wayne County
52.7
Low 7.74 / yr $326K
35 Louisa County
52.2
Low 8.16 / yr $532K
36 Keokuk County
52.0
Low 8.16 / yr $478K
37 Fremont County
51.8
Low 8.37 / yr $455K
38 Madison County
51.7
Low 7.37 / yr $371K
39 Jasper County
50.1
Low 6.53 / yr $433K
40 Iowa County
49.7
Low 6.84 / yr $437K
41 Poweshiek County
48.7
Low 6.05 / yr $410K
42 Black Hawk County
44.8
Low 3.95 / yr $330K
43 Allamakee County
43.4
Low 4.11 / yr $236K
44 Clayton County
42.6
Low 4.37 / yr $284K
45 Cedar County
42.5
Low 6.84 / yr $425K
46 Monroe County
42.4
Low 7.68 / yr $366K
47 Plymouth County
41.7
Low 6.26 / yr $278K
48 Sioux County
40.7
Low 5.89 / yr $412K
49 Fayette County
40.3
Low 4.21 / yr $210K
50 Mills County
40.0
Low 8.21 / yr $356K
51 Audubon County
36.6
Very Low 6.58 / yr $184K
52 Shelby County
36.2
Very Low 6.00 / yr $301K
53 Jackson County
35.6
Very Low 5.26 / yr $229K
54 Winneshiek County
34.6
Very Low 3.89 / yr $230K
55 Delaware County
34.0
Very Low 4.68 / yr $179K
56 Monona County
31.7
Very Low 5.58 / yr $153K
57 Dickinson County
31.5
Very Low 4.47 / yr $186K
58 Crawford County
30.7
Very Low 5.68 / yr $152K
59 Guthrie County
30.0
Very Low 6.58 / yr $213K
60 Lyon County
29.9
Very Low 5.11 / yr $206K
61 Cherokee County
27.8
Very Low 5.68 / yr $116K
62 Osceola County
26.5
Very Low 4.74 / yr $100K
63 Buena Vista County
26.3
Very Low 5.53 / yr $105K
64 Emmet County
24.8
Very Low 3.89 / yr $99K
65 Buchanan County
24.7
Very Low 4.89 / yr $150K
66 Jones County
24.4
Very Low 5.58 / yr $140K
67 Ida County
24.2
Very Low 5.74 / yr $96K
68 Chickasaw County
22.1
Very Low 4.00 / yr $78K
69 Tama County
21.6
Very Low 4.84 / yr $62K
70 O'Brien County
21.0
Very Low 5.16 / yr $119K
71 Floyd County
20.9
Very Low 3.95 / yr $64K
72 Carroll County
20.4
Very Low 5.74 / yr $74K
73 Cerro Gordo County
19.9
Very Low 3.37 / yr $59K
74 Harrison County
19.4
Very Low 6.42 / yr $56K
75 Bremer County
18.4
Very Low 3.68 / yr $96K
76 Calhoun County
17.7
Very Low 4.95 / yr $46K
77 Benton County
17.5
Very Low 6.00 / yr $79K
78 Howard County
16.7
Very Low 3.84 / yr $66K
79 Clay County
16.6
Very Low 4.84 / yr $65K
80 Mitchell County
16.2
Very Low 3.79 / yr $51K
81 Sac County
16.2
Very Low 5.11 / yr $69K
82 Greene County
15.7
Very Low 5.47 / yr $46K
83 Webster County
13.6
Very Low 4.79 / yr $35K
84 Pocahontas County
13.2
Very Low 4.53 / yr $31K
85 Story County
13.0
Very Low 5.37 / yr $37K
86 Butler County
12.8
Very Low 3.74 / yr $45K
87 Hardin County
11.1
Very Low 4.05 / yr $22K
88 Winnebago County
10.8
Very Low 3.53 / yr $20K
89 Hamilton County
10.7
Very Low 4.16 / yr $23K
90 Wright County
10.5
Very Low 3.95 / yr $19K
91 Marshall County
10.1
Very Low 4.89 / yr $18K
92 Kossuth County
10.1
Very Low 3.79 / yr $28K
93 Palo Alto County
10.0
Very Low 3.95 / yr $29K
94 Worth County
9.5
Very Low 3.37 / yr $24K
95 Humboldt County
9.4
Very Low 4.47 / yr $19K
96 Grundy County
9.4
Very Low 4.00 / yr $27K
97 Hancock County
9.0
Very Low 3.47 / yr $18K
98 Franklin County
8.3
Very Low 3.63 / yr $18K
99 Boone County
7.6
Very Low 5.26 / yr $21K

99 Iowa counties with measurable heat wave risk. See the national heat wave ranking or all Iowa counties by overall risk.

Frequently Asked Questions

Which Iowa county has the highest heat wave risk?

Polk County has the highest FEMA heat wave risk score in Iowa at 96.7 (High), with $11M in expected annual losses and about 7.32 events per year.

How many Iowa counties face significant heat wave risk?

99 Iowa counties record measurable heat wave risk in FEMA's National Risk Index; 1 of them are rated High or Very High.

Other Hazards in Iowa

Cold Wave Drought Earthquake Hail Hurricane Ice Storm Riverine Flood Landslide Lightning Strong Wind Tornado Wildfire Winter Weather