Back in 1970, most cities didn’t feel brutally hot summer days strongly influenced by the buildup of man-made carbon pollution, according to Climate Central, a nonpartisan research group.
Now, on average, cities are experiencing six extremely hot days each summer. Some cities in the Mountain West are averaging more than twice that amount, including Grand Junction, Colo. (18 days), Missoula, Mont. (17), Las Vegas (14), and Salt Lake City (13).
Not far behind are Denver (12), Albuquerque (11), Twin Falls, Idaho (11), and Tucson, Ariz. (11). Cheyenne, Wyo., and Reno, Nev., are also above the national average, with both experiencing eight extremely hot days each summer.
“When you talk about how summers now are much warmer than they used to be, they're much warmer than your parents or grandparents remember, this is what we're talking about,” said Climate Central’s Kaitlyn Trudeau. “And with heat being the leading cause of weather-related deaths, it's really important to pay attention to this.”
In 2023, a record 2,325 people died from heat in the U.S. alone, according to research led by the University of Texas at San Antonio.
Trudeau points out that extreme heat won’t be slowing down in a warming world. Levels of carbon dioxide in the atmosphere spiked in 2024, growing at the fastest annual rate on record, according to the National Oceanic and Atmospheric Administration.
“Because of burning fossil fuels, we are having more of these days than we would have otherwise,” Trudeau said. “So, as we continue to do that, as we continue to burn fossil fuels, I think it's important to remember that this will continue unless we do something.”
