Iowa lightning risk
Linn County has the highest lightning risk in Iowa, scoring 85.1 out of 100 — rated "Relatively High" by FEMA's National Risk Index. Recorded lightning events across Iowa have decreased 56% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Linn County | 85.1 | Relatively High | 1 |
| 2 | Scott County | 83.5 | Relatively High | 0 |
| 3 | Van Buren County | 81.3 | Relatively Moderate | 1 |
| 4 | Polk County | 78.1 | Relatively Moderate | 12 |
| 5 | Johnson County | 74.5 | Relatively Moderate | 0 |
| 6 | Pottawattamie County | 72.6 | Relatively Moderate | 0 |
| 7 | Muscatine County | 72.2 | Relatively Moderate | 0 |
| 8 | Jefferson County | 67.6 | Relatively Moderate | 0 |
| 9 | Des Moines County | 66.4 | Relatively Moderate | 0 |
| 10 | Henry County | 63.5 | Relatively Moderate | 0 |
| 11 | Lee County | 61.8 | Relatively Moderate | 0 |
| 12 | Warren County | 60.5 | Relatively Moderate | 2 |
| 13 | Palo Alto County | 59.2 | Relatively Moderate | 0 |
| 14 | Davis County | 57.8 | Relatively Moderate | 0 |
| 15 | Story County | 56.5 | Relatively Low | 4 |
| 16 | Black Hawk County | 54.8 | Relatively Low | 2 |
| 17 | Wapello County | 52.5 | Relatively Low | 0 |
| 18 | Clinton County | 52 | Relatively Low | 0 |
| 19 | Woodbury County | 51.7 | Relatively Low | 1 |
| 20 | Dallas County | 51 | Relatively Low | 5 |
| 21 | Washington County | 48.6 | Relatively Low | 0 |
| 22 | Appanoose County | 46.3 | Relatively Low | 0 |
| 23 | Emmet County | 38.6 | Relatively Low | 0 |
| 24 | Plymouth County | 37.2 | Relatively Low | 0 |
| 25 | Mahaska County | 35 | Relatively Low | 0 |
| 26 | Dubuque County | 34.9 | Relatively Low | 0 |
| 27 | Kossuth County | 34.4 | Relatively Low | 0 |
| 28 | Marion County | 34.3 | Relatively Low | 1 |
| 29 | Jasper County | 31.5 | Relatively Low | 0 |
| 30 | Page County | 30.5 | Relatively Low | 0 |
| 31 | Webster County | 30.4 | Relatively Low | 1 |
| 32 | Louisa County | 30.1 | Relatively Low | 0 |
| 33 | Sioux County | 29.9 | Relatively Low | 0 |
| 34 | Delaware County | 28.1 | Relatively Low | 1 |
| 35 | Madison County | 28.1 | Relatively Low | 1 |
| 36 | Keokuk County | 28 | Relatively Low | 1 |
| 37 | Crawford County | 26.9 | Relatively Low | 0 |
| 38 | Ida County | 26.9 | Relatively Low | 0 |
| 39 | Marshall County | 26.3 | Relatively Low | 1 |
| 40 | Cherokee County | 26 | Relatively Low | 0 |
| 41 | Pocahontas County | 24 | Relatively Low | 0 |
| 42 | Wright County | 23.8 | Very Low | 0 |
| 43 | Carroll County | 21.9 | Very Low | 0 |
| 44 | Fayette County | 21.7 | Very Low | 1 |
| 45 | Winnebago County | 21.6 | Very Low | 0 |
| 46 | Howard County | 21.4 | Very Low | 1 |
| 47 | Cerro Gordo County | 21 | Very Low | 4 |
| 48 | Cedar County | 20.4 | Very Low | 0 |
| 49 | Calhoun County | 20.2 | Very Low | 1 |
| 50 | Poweshiek County | 20 | Very Low | 0 |
| 51 | Winneshiek County | 20 | Very Low | 1 |
| 52 | Union County | 19.4 | Very Low | 0 |
| 53 | Buena Vista County | 19.2 | Very Low | 0 |
| 54 | Allamakee County | 19.1 | Very Low | 0 |
| 55 | Taylor County | 19 | Very Low | 0 |
| 56 | Clayton County | 18.8 | Very Low | 0 |
| 57 | O'Brien County | 18.6 | Very Low | 0 |
| 58 | Cass County | 17.6 | Very Low | 2 |
| 59 | Hamilton County | 17.5 | Very Low | 1 |
| 60 | Iowa County | 17.1 | Very Low | 0 |
| 61 | Hancock County | 17 | Very Low | 0 |
| 62 | Decatur County | 16.8 | Very Low | 0 |
| 63 | Jackson County | 16.5 | Very Low | 0 |
| 64 | Harrison County | 16.4 | Very Low | 0 |
| 65 | Floyd County | 15.9 | Very Low | 2 |
| 66 | Jones County | 15.7 | Very Low | 0 |
| 67 | Monroe County | 15.5 | Very Low | 0 |
| 68 | Lucas County | 15.1 | Very Low | 0 |
| 69 | Benton County | 15 | Very Low | 0 |
| 70 | Buchanan County | 14.9 | Very Low | 1 |
| 71 | Osceola County | 14.7 | Very Low | 1 |
| 72 | Chickasaw County | 14.2 | Very Low | 1 |
| 73 | Dickinson County | 13.8 | Very Low | 0 |
| 74 | Mills County | 13.7 | Very Low | 0 |
| 75 | Sac County | 13.7 | Very Low | 0 |
| 76 | Montgomery County | 13.3 | Very Low | 0 |
| 77 | Boone County | 13.2 | Very Low | 0 |
| 78 | Humboldt County | 12.9 | Very Low | 0 |
| 79 | Monona County | 11.8 | Very Low | 0 |
| 80 | Tama County | 11.5 | Very Low | 0 |
| 81 | Clay County | 11.4 | Very Low | 0 |
| 82 | Fremont County | 11.4 | Very Low | 0 |
| 83 | Wayne County | 11.2 | Very Low | 0 |
| 84 | Mitchell County | 10.8 | Very Low | 1 |
| 85 | Adair County | 10.2 | Very Low | 1 |
| 86 | Hardin County | 9.8 | Very Low | 1 |
| 87 | Clarke County | 9.6 | Very Low | 0 |
| 88 | Lyon County | 9.2 | Very Low | 0 |
| 89 | Greene County | 9.1 | Very Low | 0 |
| 90 | Shelby County | 8.9 | Very Low | 0 |
| 91 | Bremer County | 8.1 | Very Low | 0 |
| 92 | Audubon County | 7.3 | Very Low | 0 |
| 93 | Guthrie County | 7.3 | Very Low | 0 |
| 94 | Butler County | 6.9 | Very Low | 2 |
| 95 | Franklin County | 6.1 | Very Low | 0 |
| 96 | Adams County | 5.2 | Very Low | 0 |
| 97 | Ringgold County | 5 | Very Low | 0 |
| 98 | Grundy County | 3.4 | Very Low | 0 |
| 99 | Worth County | 3.1 | Very Low | 1 |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Lightning risk nationally:
Other hazard risks in Iowa:
Frequently asked questions
What is the highest lightning risk county in Iowa?
Linn County, IA has the highest lightning risk in Iowa, with a FEMA National Risk Index score of 85.1 out of 100 (rated "Relatively High").
What causes lightning risk in Iowa?
Lightning risk reflects expected annual losses from cloud-to-ground strikes, which ignite building fires, damage electrical systems, and cause fatalities. Florida consistently leads the US in lightning density. High scores also appear across the Gulf Coast, Southeast, and central Plains, where afternoon convective storms are most frequent in summer months.