Climate Change Raises Rates of U.S. Emergency Room Visits For Heat Illness

New research from Climate Central indicates that climate change accounted for 27% of the rate of heat-related emergency room visits in the U.S. during the warm seasons from 2018 to 2025. The study found that all U.S. regions experienced increased visit rates due to climate change, with the highest rates occurring in southern and western states. A notable peak occurred during the June 2021 northwestern U.S. heat wave, where daily visit rates were approximately 50 times higher than the regional average, with 27% of that rate attributed to climate change.

• Between 2018 and 2025, climate change was responsible for 27% of the rate of heat-related emergency room visits in the U.S. during the warm season (April to October).
• Southern and western states (Regions 6 and 9) saw the highest average rates of heat-related emergency room visits, with climate change contributing to approximately one-quarter of those rates. Region 6—comprising Arkansas, Louisiana, New Mexico, Oklahoma, and Texas—had the highest rate of visits due to climate change, averaging 225 visits per 100,000 ER visits per day, compared to a counterfactual rate of 168 in a world without human-caused climate change.
• The June 2021 heat wave in the northwestern U.S. (Region 10: Alaska, Idaho, Oregon, and Washington) produced the highest daily rates of heat-related ER visits of the eight-year study period. From June 27 to 29, 2021, the average daily rate was 4,710 visits per 100,000, which is roughly 50 times the region's typical warm-season daily rate of 94 per 100,000; climate change accounted for 27% of this rate.
• Heat illness generally results in an average of over 67,000 emergency room visits annually in the U.S., with the rate of these visits increasing by nearly 3% on average each year from 2008 to 2020.

APA

Saha, S., & Rublee, C. (2026). Climate Change Raises Rates of U.S. Emergency Room Visits For Heat Illness. Climate Central. https://www.climatecentral.org/climate-matters/heat-illness-emergency-room-visits

Chicago

Saha, Shubhayu, and Caitlin Rublee. Climate Change Raises Rates of U.S. Emergency Room Visits For Heat Illness. Climate Central, 2026. https://www.climatecentral.org/climate-matters/heat-illness-emergency-room-visits.

Wikipedia

{{cite report |last1=Saha |first1=Shubhayu |last2=Rublee |first2=Caitlin |title=Climate Change Raises Rates of U.S. Emergency Room Visits For Heat Illness |publisher=Climate Central |date=9 September 2026 |url=https://www.climatecentral.org/climate-matters/heat-illness-emergency-room-visits |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{saha2026climate, author = {Saha, Shubhayu and Rublee, Caitlin}, title = {{Climate Change Raises Rates of U.S. Emergency Room Visits For Heat Illness}}, institution = {Climate Central}, year = {2026}, month = sep, url = {https://www.climatecentral.org/climate-matters/heat-illness-emergency-room-visits}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }