Regions in the U.S. Where Heat-Related ER Visits Are Most Common

Heat is the deadliest climate-related hazard in the United States—and official numbers may not reflect the full scale of the problem. Data from the Centers for Disease Control and Prevention shows that an average of 1,700 Americans are killed by heat every year. But a recent investigation conducted by NPR and Boston University found that the role heat plays in many fatalities is often obscured by other more obvious conditions, both chronic and acute; and the true number of heat-related deaths is likely closer to 9,000 per year. 

While the accuracy of official heat fatality data may be disputable, what is clear is that heat is taking a greater toll on as temperatures rise. Official government records show that between 2004 and 2018, the average heat-related fatality rate was about 700 per year, less than half of what it is now. And from a public health perspective, heat fatalities are only the tip of the iceberg. 

A recent report from the non-profit research and advocacy group Climate Central found that between the months of April in October, from 2018 to 2025, there were 130 heat-related emergency room visits per day for every 100,000 ER visits nationwide, on average. The report also found that 27% of heat-related ER visits in the last eight years were attributable to climate change. In some parts of the country, heat-related illness accounts for a far larger-than-average share of emergency room visits. 

Using data from Climate Central, Climate Crisis 247 identified the regions of the country where heat-related ER visits are most common. We ranked all 10 regions included in the report on the average daily number of heat-related ER visits for every 100,000 ER visits. Rankings are based on reported statistics from 2018 to 2025, and only ER visits between the months of April and October were considered. All supplemental data in this story is from Climate Central. It is important to note that some regions include data from U.S. territories, though for the purposes of this story, only U.S. states are listed. 

10. Coastal Northeast

• Average daily heat-related emergency room visits, April-October: 53 per 100,000 ER visits (approx. 41% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 24, 2025
• Heat-related emergency room visits on June 24, 2025:  1,429  per 100,000 ER visits (approx. 35% due to climate change)
• Average regional temperature on June 24, 2025: 95.0°F (93.2°F estimated avg. without climate change)
• States in region: New Jersey, New York

9. New England

• Average daily heat-related emergency room visits, April-October: 67 per 100,000 ER visits (approx. 37% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 24, 2025
• Heat-related emergency room visits on June 24, 2025:  2,011  per 100,000 ER visits (approx. 26% due to climate change)
• Average regional temperature on June 24, 2025: 95.5°F (93.9°F estimated avg. without climate change)
• States in region: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont

8. Mountain

• Average daily heat-related emergency room visits, April-October: 84 per 100,000 ER visits (approx. 29% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: July 12, 2024
• Heat-related emergency room visits on July 12, 2024:  894  per 100,000 ER visits (approx. 33% due to climate change)
• Average regional temperature on July 12, 2024: 95.0°F (91.6°F estimated avg. without climate change)
• States in region: Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming

7. Upper Midwest

• Average daily heat-related emergency room visits, April-October: 85 per 100,000 ER visits (approx. 30% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 22, 2025
• Heat-related emergency room visits on June 22, 2025:  1,396  per 100,000 ER visits (approx. 26% due to climate change)
• Average regional temperature on June 22, 2025: 91.8°F (90.3°F estimated avg. without climate change)
• States in region: Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin

6. Northwest

• Average daily heat-related emergency room visits, April-October: 94 per 100,000 ER visits (approx. 35% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 28, 2021
• Heat-related emergency room visits on June 28, 2021:  6,763  per 100,000 ER visits (approx. 27% due to climate change)
• Average regional temperature on June 28, 2021: 98.8°F (96.8°F estimated avg. without climate change)
• States in region: Alaska, Idaho, Oregon, Washington

5. Mid-Atlantic

• Average daily heat-related emergency room visits, April-October: 108 per 100,000 ER visits (approx. 33% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 24, 2025
• Heat-related emergency room visits on June 24, 2025:  1,828  per 100,000 ER visits (approx. 30% due to climate change)
• Average regional temperature on June 24, 2025: 96.4°F (94.6°F estimated avg. without climate change)
• States in region: Delaware, Maryland, Pennsylvania, Virginia, West Virginia

4. Southeast

• Average daily heat-related emergency room visits, April-October: 155 per 100,000 ER visits (approx. 25% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 25, 2025
• Heat-related emergency room visits on June 25, 2025:  1,185  per 100,000 ER visits (approx. 27% due to climate change)
• Average regional temperature on June 25, 2025: 92.8°F (91.0°F estimated avg. without climate change)
• States in region: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee

3. Central Midwest

• Average daily heat-related emergency room visits, April-October: 199 per 100,000 ER visits (approx. 20% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: August 22, 2023
• Heat-related emergency room visits on August 22, 2023:  2,772  per 100,000 ER visits (approx. 19% due to climate change)
• Average regional temperature on August 22, 2023: 96.4°F (95.2°F estimated avg. without climate change)
• States in region: Iowa, Kansas, Missouri, Nebraska

2. West South-Central

• Average daily heat-related emergency room visits, April-October: 225 per 100,000 ER visits (approx. 25% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: June 27, 2023
• Heat-related emergency room visits on June 27, 2023:  1,256  per 100,000 ER visits (approx. 23% due to climate change)
• Average regional temperature on June 27, 2023: 98.1°F (96.3°F estimated avg. without climate change)
• States in region: Arkansas, Louisiana, New Mexico, Oklahoma, Texas

1. Western and Southern Coastal

• Average daily heat-related emergency room visits, April-October: 230 per 100,000 ER visits (approx. 23% due to climate change)
• Worst day for heat related emergency room visits, 2018-2025: July 22, 2023
• Heat-related emergency room visits on July 22, 2023:  1,605  per 100,000 ER visits (approx. 20% due to climate change)
• Average regional temperature on July 22, 2023: 92.3°F (90.5°F estimated avg. without climate change)
• States in region: Arizona, California, Hawaii, Nevada