US Counties Where the Most People Die From Extreme Heat
https://climate-crisis-247-bucket.nyc3.cdn.digitaloceanspaces.com/wp-content/uploads/2025/06/07214455/od9eozfsoh0-150x150.jpgThis week, the first extreme heat wave of the summer is impacting nearly one fourth of the country. Temperatures pushed past 100°F in dozens of major metros on Tuesday – with some cities experiencing triple-digit heat for the first time in recorded history – as the National Weather Service issued heat warnings in nearly 500 counties, representing more than 96 million Americans.
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Extreme heat is becoming harder to ignore, and is exacting a larger human toll every year. Hundreds of Americans die from heat exposure annually, and thousands are sent to the emergency room for heat-related illness. While heat deaths are not tallied uniformly from county to county, a look at CDC mortality data reveals the places where the most Americans die from heat exposure every year.
To determine the counties where the most people die due to excessive heat, Climate Crisis 247 reviewed data on mortality from the Centers for Disease Control and Prevention’s WONDER database. Counties were ranked based on the total number of reported deaths due exposure to excessive natural heat (hyperthermia) from 2018 to 2013. Supplemental data on average daily maximum temperature are from NOAA’s National Centers for Environmental Information. Population data is from the U.S. Census Bureau.
25. Navajo County, AZ
- Mortality due to excessive heat, 2018-2023: 17 deaths
- Excessive heat mortality rate: 2.6 deaths per 100,000 residents
- Average summer daily high, 2024: 74.7°F
- Total population: 107,744
- County seat: Holbrook
24. Broward County, FL
- Mortality due to excessive heat, 2018-2023: 18 deaths
- Excessive heat mortality rate: 0.2 deaths per 100,000 residents
- Average summer daily high, 2024: 84.1°F
- Total population: 1,946,127
- County seat: Fort Lauderdale
23. Clackamas County, OR
- Mortality due to excessive heat, 2018-2023: 18 deaths
- Excessive heat mortality rate: 0.7 deaths per 100,000 residents
- Average summer daily high, 2024: 63.2°F
- Total population: 422,308
- County seat: Oregon City
22. Imperial County, CA
- Mortality due to excessive heat, 2018-2023: 19 deaths
- Excessive heat mortality rate: 1.8 deaths per 100,000 residents
- Average summer daily high, 2024: 95.2°F
- Total population: 179,319
- County seat: El Centro
21. Denton County, TX
- Mortality due to excessive heat, 2018-2023: 20 deaths
- Excessive heat mortality rate: 0.4 deaths per 100,000 residents
- Average summer daily high, 2024: 85.3°F
- Total population: 945,644
- County seat: Denton
20. La Paz County, AZ
- Mortality due to excessive heat, 2018-2023: 21 deaths
- Excessive heat mortality rate: 18.5 deaths per 100,000 residents
- Average summer daily high, 2024: 94.4°F
- Total population: 16,605
- County seat: Parker
19. Cook County, IL
- Mortality due to excessive heat, 2018-2023: 26 deaths
- Excessive heat mortality rate: 0.1 deaths per 100,000 residents
- Average summer daily high, 2024: 73.1°F
- Total population: 5,185,812
- County seat: Chicago
18. Kern County, CA
- Mortality due to excessive heat, 2018-2023: 26 deaths
- Excessive heat mortality rate: 0.5 deaths per 100,000 residents
- Average summer daily high, 2024: 82.1°F
- Total population: 910,433
- County seat: Bakersfield
17. Webb County, TX
- Mortality due to excessive heat, 2018-2023: 27 deaths
- Excessive heat mortality rate: 1.7 deaths per 100,000 residents
- Average summer daily high, 2024: 87.9°F
- Total population: 267,731
- County seat: Laredo
16. Spokane County, WA
- Mortality due to excessive heat, 2018-2023: 28 deaths
- Excessive heat mortality rate: 0.9 deaths per 100,000 residents
- Average summer daily high, 2024: 67.1°F
- Total population: 544,323
- County seat: Spokane
15. King County, WA
- Mortality due to excessive heat, 2018-2023: 34 deaths
- Excessive heat mortality rate: 0.3 deaths per 100,000 residents
- Average summer daily high, 2024: 61.6°F
- Total population: 2,262,713
- County seat: Seattle
14. San Diego County, CA
- Mortality due to excessive heat, 2018-2023: 35 deaths
- Excessive heat mortality rate: 0.2 deaths per 100,000 residents
- Average summer daily high, 2024: 77.3°F
- Total population: 3,282,782
- County seat: San Diego
13. San Bernardino County, CA
- Mortality due to excessive heat, 2018-2023: 45 deaths
- Excessive heat mortality rate: 0.3 deaths per 100,000 residents
- Average summer daily high, 2024: 89.0°F
- Total population: 2,187,816
- County seat: San Bernardino
12. Pinal County, AZ
- Mortality due to excessive heat, 2018-2023: 48 deaths
- Excessive heat mortality rate: 1.7 deaths per 100,000 residents
- Average summer daily high, 2024: 89.7°F
- Total population: 449,219
- County seat: Florence
11. Los Angeles County, CA
- Mortality due to excessive heat, 2018-2023: 59 deaths
- Excessive heat mortality rate: 0.1 deaths per 100,000 residents
- Average summer daily high, 2024: 76.7°F
- Total population: 9,848,406
- County seat: Los Angeles
10. Dallas County, TX
- Mortality due to excessive heat, 2018-2023: 60 deaths
- Excessive heat mortality rate: 0.4 deaths per 100,000 residents
- Average summer daily high, 2024: 85.0°F
- Total population: 2,603,816
- County seat: Dallas
9. Riverside County, CA
- Mortality due to excessive heat, 2018-2023: 66 deaths
- Excessive heat mortality rate: 0.4 deaths per 100,000 residents
- Average summer daily high, 2024: 88.7°F
- Total population: 2,449,909
- County seat: Riverside
8. Yuma County, AZ
- Mortality due to excessive heat, 2018-2023: 66 deaths
- Excessive heat mortality rate: 5.2 deaths per 100,000 residents
- Average summer daily high, 2024: 94.0°F
- Total population: 207,685
- County seat: Yuma
7. Multnomah County, OR
- Mortality due to excessive heat, 2018-2023: 85 deaths
- Excessive heat mortality rate: 1.8 deaths per 100,000 residents
- Average summer daily high, 2024: 66.2°F
- Total population: 803,863
- County seat: Portland
6. Harris County, TX
- Mortality due to excessive heat, 2018-2023: 89 deaths
- Excessive heat mortality rate: 0.3 deaths per 100,000 residents
- Average summer daily high, 2024: 84.6°F
- Total population: 4,758,579
- County seat: Houston
5. Tarrant County, TX
- Mortality due to excessive heat, 2018-2023: 89 deaths
- Excessive heat mortality rate: 0.7 deaths per 100,000 residents
- Average summer daily high, 2024: 85.2°F
- Total population: 2,135,743
- County seat: Fort Worth
4. Pima County, AZ
- Mortality due to excessive heat, 2018-2023: 113 deaths
- Excessive heat mortality rate: 1.8 deaths per 100,000 residents
- Average summer daily high, 2024: 87.2°F
- Total population: 1,049,947
- County seat: Tucson
3. Mohave County, AZ
- Mortality due to excessive heat, 2018-2023: 239 deaths
- Excessive heat mortality rate: 18.4 deaths per 100,000 residents
- Average summer daily high, 2024: 85.7°F
- Total population: 217,420
- County seat: Kingman
2. Clark County, NV
- Mortality due to excessive heat, 2018-2023: 391 deaths
- Excessive heat mortality rate: 2.8 deaths per 100,000 residents
- Average summer daily high, 2024: 88.6°F
- Total population: 2,293,764
- County seat: Las Vegas
1. Maricopa County, AZ
- Mortality due to excessive heat, 2018-2023: 648 deaths
- Excessive heat mortality rate: 2.4 deaths per 100,000 residents
- Average summer daily high, 2024: 92.5°F
- Total population: 4,491,987
- County seat: Phoenix
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