10 Counties Where Americans Greatly Underestimate The Risks Of Extreme Heat

Of all severe weather conditions reported in the United States, heat is by far the deadliest. According to the National Oceanic and Atmospheric Administration, extreme heat was linked to 529 deaths in the U.S. in 2024 alone – more than the total number of fatalities attributed to nearly every other natural disaster or climate condition combined. Unlike floods, hurricanes, lightning, or tornadoes, the dangers associated with extreme heat are not visually perceptible, and as a result, heat’s attendant risks are often greatly underestimated. 

The threshold for extreme heat, as defined by the Environmental Protection Agency, is 95°F. At temperatures of 96°F or higher, the human body can struggle to cool itself, particularly in humid environments. Prolonged exposure to such temperatures can lead to dehydration, reduced blood pressure, and low blood flow – conditions which can ultimately result in heart attack, organ failure or heat stroke. 

Dangerously high temperatures can occur virtually anywhere in the continental U.S. during the summer season, but certain socioeconomic and demographic factors can make certain populations especially vulnerable. These include age, income, preexisting conditions, and access to healthcare. Understanding the existential danger high temperatures can pose is critical to avoiding the most dire consequences. However, in many parts of the United States that are home to high-risk populations and are regularly exposed to extreme heat, the vast majority of residents are unconcerned about extreme heat. 

Using data from the Heat Risk Perception Gap report, published by the Yale Program on Climate Change Communication, Climate Crisis 247 identified the counties where Americans are greatly underestimating the risks of extreme heat. Counties are ranked on the difference between the share of residents who are concerned about extreme heat and local extreme heat vulnerability – a composite index score comprising 25 measures, including historical heat exposure, heat-related illnesses, the prevalence of certain preexisting conditions, and multiple relevant social, economic, and demographic indicators. A full methodology is available here. Supplemental data on local summer temperatures and warming trends are from NOAA and Climate Central. 

Only the 10 U.S. counties with the largest gaps between risk and perception rank on this list. Counties are ranked in the order noted by YPCCC. 

10. Coos County, Oregon

• Extreme heat vulnerability index score: 87 out of 100
• Share of population concerned about risks associated with extreme heat: 29%
• Change in average summer temperature, 1970-2024: +3°F
• Average daily high in summer season, 1901-2000: 71.2°F
• Highest recorded summer temperature, 2000-2025: 100°F (July 28, 2009)

9. Boyd County, Kentucky

• Extreme heat vulnerability index score: 86 out of 100
• Share of population concerned about risks associated with extreme heat: 26%
• Change in average summer temperature, 1970-2024: +2.4°F
• Average daily high in summer season, 1901-2000: 84.7°F
• Highest recorded summer temperature, 2000-2025: 104°F (August 15, 2005)

8. Jackson County, Ohio

• Extreme heat vulnerability index score: 82 out of 100
• Share of population concerned about risks associated with extreme heat: 23%
• Change in average summer temperature, 1970-2024: +1.1°F
• Average daily high in summer season, 1901-2000: 84°F
• Highest recorded summer temperature, 2000-2025: 101°F (July 8, 2012)

7. Morgan County, Ohio

• Extreme heat vulnerability index score: 81 out of 100
• Share of population concerned about risks associated with extreme heat: 21%
• Change in average summer temperature, 1970-2024: +1.6°F
• Average daily high in summer season, 1901-2000: 83.4°F
• Highest recorded summer temperature, 2000-2025: 98°F (August 14, 2005)

6. Sherman County, Oregon

• Extreme heat vulnerability index score: 92 out of 100
• Share of population concerned about risks associated with extreme heat: 31%
• Change in average summer temperature, 1970-2024: +3.4°F
• Average daily high in summer season, 1901-2000: 80.6°F
• Highest recorded summer temperature, 2000-2025: 113°F (June 29, 2021)

5. Blackford County, Indiana

• Extreme heat vulnerability index score: 84 out of 100
• Share of population concerned about risks associated with extreme heat: 22%
• Change in average summer temperature, 1970-2024: +1°F
• Average daily high in summer season, 1901-2000: 83.1°F
• Highest recorded summer temperature, 2000-2025: 104°F (June 29, 2012)

4. Gilliam County, Oregon

• Extreme heat vulnerability index score: 94 out of 100
• Share of population concerned about risks associated with extreme heat: 32%
• Change in average summer temperature, 1970-2024: +3.4°F
• Average daily high in summer season, 1901-2000: 81.2°F
• Highest recorded summer temperature, 2000-2025: 117°F (June 30, 2021)

3. Wise County, Virginia

• Extreme heat vulnerability index score: 90 out of 100
• Share of population concerned about risks associated with extreme heat: 28%
• Change in average summer temperature, 1970-2024: +1.5°F
• Average daily high in summer season, 1901-2000: 80.2°F
• Highest recorded summer temperature, 2000-2025: 102°F (July 1, 2012)

2. Bristol City, Virginia

• Extreme heat vulnerability index score: 98 out of 100
• Share of population concerned about risks associated with extreme heat: 31%
• Change in average summer temperature, 1970-2024: +2.2°F
• Average daily high in summer season, 1901-2000: 83.9°F
• Highest recorded summer temperature, 2000-2025: 103°F (June 30, 2012)

1. Norton City, Virginia

• Extreme heat vulnerability index score: 99 out of 100
• Share of population concerned about risks associated with extreme heat: 28%
• Change in average summer temperature, 1970-2024: +1.5°F
• Average daily high in summer season, 1901-2000: 80°F
• Highest recorded summer temperature, 2000-2025: 99°F (July 7, 2025)