The 10 States With the Most Heat-Related Deaths

July 2026 now stands as the hottest month in U.S. history. According to the National Oceanic and Atmospheric Administration, the average temperature across the Lower 48 was 76.9°F last month – exceeding the previous record of 76.8°F that has stood for nearly a century. Additionally, the average daily high in the continental U.S. in July 2026 was 89.5°F, nearly three 3°F above the 20th century average for the month. 

Heat is the leading climate-related cause of death in the United States, and while official, nationwide fatality figures for the summer are not yet available, local reports show that that record-breaking heat has taken a devastating toll. According to officials in Maricopa County, Arizona, there have been 81 local heat-related deaths so far this year, more than double the number reported at the same point in 2025. 

Maricopa County–home to the city of Phoenix–is one of a small handful of places in the U.S. where temperatures regularly top 100°F during the summer months. Local residents who spend time outdoors, or do not have access to air conditioning, are at especially high risk of heat-related illness or death. Due in part to dangerously high temperatures in Maricopa County, Arizona ranks among the states with the highest heat-related fatality rates. 

Using data from the Centers for Disease Control and Prevention, Climate Crisis 247 identified the states where the most people die from exposure to excessive heat. We ranked all 50 states on the number of heat-related fatalities per 100,000 residents between 2018 and 2024. Only the 10 highest ranking states are listed. Supplemental county-level data is also from the CDC. In addition, we listed historical average daily summer highs using data from NOAA, and the share of households without air conditioning with data from the Census’ Local Air Conditioning Estimates program.

10. Florida

• Heat related deaths, 2018-2024: 0.1 per 100,000 people (207 total)
• Households in Florida with no air conditioning: 0.5% (42,615 total)
• County in state with the highest heat-related death rate, 2018-2024: Escambia County; 0.4 heat-related fatalities per 100,000 people (10 total)
• Households in Escambia County with no air conditioning: 0.7% (898 total)
• Historical avg. summertime daily high in Escambia County: 90.4°F in 2025, 90.4°F in 20th century

9. California

• Heat related deaths, 2018-2024: 0.2 per 100,000 people (515 total)
• Households in California with no air conditioning: 21.4% (2,873,171 total)
• County in state with the highest heat-related death rate, 2018-2024: Imperial County; 1.7 heat-related fatalities per 100,000 people (22 total)
• Households in Imperial County with no air conditioning: 0.6% (293 total)
• Historical avg. summertime daily high in Imperial County: 107.2°F in 2025, 104.0°F in 20th century

8. Missouri

• Heat related deaths, 2018-2024: 0.2 per 100,000 people (108 total)
• Households in Missouri with no air conditioning: 0.9% (22,438 total)
• County in state with the highest heat-related death rate, 2018-2024: Jackson County; 0.2 heat-related fatalities per 100,000 people (11 total)
• Households in Jackson County with no air conditioning: 0.9% (2,717 total)
• Historical avg. summertime daily high in Jackson County: 86.3°F in 2025, 86.7°F in 20th century

7. Washington

• Heat related deaths, 2018-2024: 0.3 per 100,000 people (163 total)
• Households in Washington with no air conditioning: 34.2% (1,033,388 total)
• County in state with the highest heat-related death rate, 2018-2024: Spokane County; 0.9 heat-related fatalities per 100,000 people (33 total)
• Households in Spokane County with no air conditioning: 2.2% (4,739 total)
• Historical avg. summertime daily high in Spokane County: 83.4°F in 2025, 78.9°F in 20th century

6. Louisiana

• Heat related deaths, 2018-2024: 0.4 per 100,000 people (138 total)
• Households in Louisiana with no air conditioning: 0.9% (16,061 total)
• County in state with the highest heat-related death rate, 2018-2024: Caddo Parish; 0.7 heat-related fatalities per 100,000 people (12 total)
• Households in Caddo Parish with no air conditioning: 1.7% (1,609 total)
• Historical avg. summertime daily high in Caddo Parish: 93.0°F in 2025, 92.6°F in 20th century

5. Texas

• Heat related deaths, 2018-2024: 0.4 per 100,000 people (772 total)
• Households in Texas with no air conditioning: 1.0% (108,020 total)
• County in state with the highest heat-related death rate, 2018-2024: Webb County; 1.5 heat-related fatalities per 100,000 people (28 total)
• Households in Webb County with no air conditioning: 0.6% (478 total)
• Historical avg. summertime daily high in Webb County: 99.1°F in 2025, 97.7°F in 20th century

4. Mississippi

• Heat related deaths, 2018-2024: 0.5 per 100,000 people (104 total)
• Households in Mississippi with no air conditioning: 1.1% (12,364 total)
• County in state with the highest heat-related death rate, 2018-2024: Washington County; 5.6 heat-related fatalities per 100,000 people (17 total)
• Households in Washington County with no air conditioning: 3.0% (517 total)
• Historical avg. summertime daily high in Washington County: 93.5°F in 2025, 91.8°F in 20th century

3. Oregon

• Heat related deaths, 2018-2024: 0.6 per 100,000 people (172 total)
• Households in Oregon with no air conditioning: 18.1% (307,804 total)
• County in state with the highest heat-related death rate, 2018-2024: Multnomah County; 1.6 heat-related fatalities per 100,000 people (89 total)
• Households in Multnomah County with no air conditioning: 13.2% (45,851 total)
• Historical avg. summertime daily high in Multnomah County: 79.1°F in 2025, 75.0°F in 20th century

2. Nevada

• Heat related deaths, 2018-2024: 2.5 per 100,000 people (543 total)
• Households in Nevada with no air conditioning: 3.9% (46,010 total)
• County in state with the highest heat-related death rate, 2018-2024: Nye County; 5.6 heat-related fatalities per 100,000 people (20 total)
• Households in Nye County with no air conditioning: 4.7% (1,030 total)
• Historical avg. summertime daily high in Nye County: 88.9°F in 2025, 85.7°F in 20th century

1. Arizona

• Heat related deaths, 2018-2024: 3.0 per 100,000 people (1,563 total)
• Households in Arizona with no air conditioning: 2.0% (56,133 total)
• County in state with the highest heat-related death rate, 2018-2024: La Paz County; 22.3 heat-related fatalities per 100,000 people (29 total)
• Households in La Paz County with no air conditioning: 1.1% (97 total)
• Historical avg. summertime daily high in La Paz County: 105.7°F in 2025, 102.9°F in 20th century