The States Where Heat Kills the Most People

Extreme heat kills several hundred thousand people a year worldwide, though the data is imperfect—death certificates often list related causes, such as heart disease, rather than heat itself. According to one of the most widely regarded scientific studies, published in The Lancet, approximately 550,000 people die from heat-related illnesses worldwide each year. The authors wrote, “The higher temperatures and the increasing size of vulnerable populations have led to a 63% increase in heat-related deaths since the 1990s, reaching an estimated 546,000 yearly deaths on average in 2012–21.”

Very few of these deaths occur in the US. Unlike nations such as India, America rarely experiences multiple weeks of extreme heat across urban populations that can run into the tens of millions—most of the country is still temperate. In fact, medical experts put the American heat death toll relatively low. JAMA reports that 21,518 people died from heat between 1999 and 2023, or about 900 per year.

Different studies on US heat deaths produce different results. In 2023, 579 people died from heat-related causes in Maricopa County, home to Phoenix. The county’s figures are considered uniquely accurate. According to The Guardian, “There is no accurate nationwide heat death toll, and Maricopa county produces the country’s most detailed heat mortality and morbidity information.” Many of those who died were homeless, and some died at home without the benefit of air conditioning. Other studies have pointed out that in many of the hottest parts of the US, residents don’t always have enough money to run their air conditioning units.

The heat death issue was on full display as temperatures topped 100 degrees in many US cities during a stretch when three heat domes covered parts of the country. High-temperature records were broken as far east as New York City and as far west as Southern California. In South Dakota, one newspaper described last week’s heat as “record shattering.”

Rising heat deaths raise a number of economic and policy questions, including how people can be protected during periods of extreme heat. It’s not possible to check on every apartment and home in a city when several days in a row break records. In some cities, people can go to cooling centers instead. A recent CDC study looked at where these might be located: “Key locations typically include public libraries, senior centers, and community buildings.”

As temperatures across the world—and the US specifically—continue to rise, heat deaths will likely rise with them. Climatecrisis247 looked at the states with the most heat deaths on a per-100,000 basis. We also examined each state’s all-time high temperature and, most importantly, the average number of days per year with a high temperature of 90 degrees or greater—the point at which, according to Georgetown University, heat stroke often begins.

Phoenix typically sees more than 100 days a year with temperatures above 100 degrees Fahrenheit, and the Maricopa County data underscores how deadly the city can be in summer. It’s no surprise, then, that Arizona tops this list.

Rank	State	HRI Deaths per 100k	All-Time Max Temp (°F)	Avg Days Above 90°F/yr
1	Arizona	23.54	128	167
2	Nevada	19.81	125	109
3	Arkansas	2.94	120	65
4	New Mexico	2.85	122	75
5	California	1.48	134	62
6	Oklahoma	2.11	120	72
7	Texas	1.87	120	79
8	Louisiana	2.44	114	68
9	Oregon	3.93	119	14
10	Kansas	1.47	121	50

Information is for the 2018–2022 study period. Data sourced from the CDC WONDER Underlying Cause of Death Database, NOAA NCEI Climate Extremes Records, and NOAA NCEI 1991–2020 U.S. Climate Normals. Analysis source: Ladah Injury & Car Accident Lawyers.