Wisconsin heat wave risk
Milwaukee County has the highest heat wave risk in Wisconsin, scoring 99 out of 100 — rated "Relatively High" by FEMA's National Risk Index. Recorded heat wave events across Wisconsin have increased 18% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Milwaukee County | 99 | Relatively High | 14 |
| 2 | Dane County | 95.3 | Relatively Moderate | 12 |
| 3 | Juneau County | 95.1 | Relatively Moderate | 4 |
| 4 | Waukesha County | 90.4 | Relatively Moderate | 11 |
| 5 | La Crosse County | 88.5 | Relatively Moderate | 5 |
| 6 | Racine County | 83 | Relatively Moderate | 13 |
| 7 | Rock County | 80.8 | Relatively Moderate | 12 |
| 8 | Columbia County | 80.4 | Relatively Moderate | 11 |
| 9 | Kenosha County | 80.4 | Relatively Moderate | 13 |
| 10 | Manitowoc County | 79.9 | Relatively Moderate | 2 |
| 11 | Barron County | 76.3 | Relatively Low | 0 |
| 12 | Monroe County | 76.1 | Relatively Low | 4 |
| 13 | Brown County | 76 | Relatively Low | 2 |
| 14 | Crawford County | 75.8 | Relatively Low | 5 |
| 15 | Winnebago County | 75 | Relatively Low | 2 |
| 16 | Walworth County | 74 | Relatively Low | 12 |
| 17 | Dodge County | 72.7 | Relatively Low | 11 |
| 18 | Adams County | 72.4 | Relatively Low | 3 |
| 19 | Washington County | 72 | Relatively Low | 10 |
| 20 | Fond du Lac County | 71.4 | Relatively Low | 10 |
| 21 | Jefferson County | 71.3 | Relatively Low | 11 |
| 22 | Outagamie County | 71.1 | Relatively Low | 2 |
| 23 | Sheboygan County | 68 | Relatively Low | 9 |
| 24 | Sauk County | 67.5 | Relatively Low | 12 |
| 25 | Eau Claire County | 67.4 | Relatively Low | 1 |
| 26 | Vernon County | 66.9 | Relatively Low | 5 |
| 27 | Richland County | 65.2 | Relatively Low | 4 |
| 28 | Grant County | 63 | Relatively Low | 5 |
| 29 | Marathon County | 62.8 | Relatively Low | 1 |
| 30 | Marquette County | 62.7 | Relatively Low | 11 |
| 31 | Douglas County | 61.4 | Relatively Low | 1 |
| 32 | Trempealeau County | 60.6 | Relatively Low | 5 |
| 33 | Polk County | 60.1 | Relatively Low | 3 |
| 34 | Clark County | 58.3 | Relatively Low | 0 |
| 35 | Ozaukee County | 56 | Relatively Low | 9 |
| 36 | Green Lake County | 54.9 | Relatively Low | 11 |
| 37 | Dunn County | 54.8 | Relatively Low | 1 |
| 38 | Chippewa County | 54.6 | Relatively Low | 0 |
| 39 | Waupaca County | 54.6 | Relatively Low | 2 |
| 40 | Jackson County | 53.4 | Relatively Low | 4 |
| 41 | Green County | 52.3 | Relatively Low | 12 |
| 42 | Wood County | 49.6 | Relatively Low | 2 |
| 43 | St. Croix County | 48.9 | Relatively Low | 3 |
| 44 | Calumet County | 46.2 | Relatively Low | 1 |
| 45 | Waushara County | 44.2 | Relatively Low | 2 |
| 46 | Iowa County | 43.8 | Relatively Low | 12 |
| 47 | Portage County | 43.1 | Relatively Low | 2 |
| 48 | Shawano County | 41.8 | Relatively Low | 1 |
| 49 | Burnett County | 38.6 | Very Low | 1 |
| 50 | Lafayette County | 38.4 | Very Low | 11 |
| 51 | Pierce County | 35.4 | Very Low | 2 |
| 52 | Sawyer County | 33.2 | Very Low | 1 |
| 53 | Washburn County | 32.6 | Very Low | 1 |
| 54 | Taylor County | 31.4 | Very Low | 0 |
| 55 | Bayfield County | 31.3 | Very Low | 1 |
| 56 | Buffalo County | 30 | Very Low | 5 |
| 57 | Rusk County | 28.9 | Very Low | 0 |
| 58 | Oconto County | 28.2 | Very Low | 1 |
| 59 | Marinette County | 23.8 | Very Low | 0 |
| 60 | Ashland County | 23.2 | Very Low | 1 |
| 61 | Pepin County | 22.9 | Very Low | 2 |
| 62 | Price County | 20.6 | Very Low | 1 |
| 63 | Kewaunee County | 19.6 | Very Low | 1 |
| 64 | Lincoln County | 18.6 | Very Low | 0 |
| 65 | Langlade County | 16 | Very Low | 0 |
| 66 | Oneida County | 14.8 | Very Low | 0 |
| 67 | Menominee County | 14.6 | Very Low | 0 |
| 68 | Vilas County | 12.7 | Very Low | 0 |
| 69 | Iron County | 11.4 | Very Low | 2 |
| 70 | Door County | 9.5 | Very Low | 1 |
| 71 | Forest County | 7.5 | Very Low | 0 |
| 72 | Florence County | 4.7 | 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.
Heat Wave risk nationally:
Other hazard risks in Wisconsin:
Frequently asked questions
What is the highest heat wave risk county in Wisconsin?
Milwaukee County, WI has the highest heat wave risk in Wisconsin, with a FEMA National Risk Index score of 99 out of 100 (rated "Relatively High").
What causes heat wave risk in Wisconsin?
Heat is consistently the leading cause of weather-related mortality in the US, yet it remains underrepresented in federal disaster declarations relative to its actual impact. High scores reflect a combination of extreme temperature exposure, population vulnerability (elderly, outdoor workers), and limited access to cooling infrastructure.