Many Americans have likely noticed that it’s much hotter than normal for this time of year. As of Monday, July 20, excessive heat warnings and advisories had been issued for much of the East Coast, affecting around 70 million people from Maine to South Carolina.
Temperatures are forecast to exceed 90 degrees for much of the country throughout the rest of the week, according to the National Weather Service, and in some cases — such as in the Desert Southwest — even 100 degrees.
While warm and even hot weather can be enjoyable, extreme heat puts many — especially infants, young children, and older adults — at risk of heat-related illnesses. The frequency of heat-related health issues, such as heat stroke and exhaustion, is directly related to how high temperatures are and the level of humidity. According to the Department of Homeland Security, extreme heat often results in a greater number of annual deaths than any other weather-related hazard.
24/7 Wall St. has identified the country’s 50 hottest cities (with populations of at least 10,000) based on the average number of 90-plus degree days per year using climate data from the National Oceanic and Atmospheric Administration.
In the 50 large cities on the list, the temperature reaches at least 90 degrees Fahrenheit for an average of 67 days or more per year. In some of these cities, the temperature is this high in more than double that number of days (and more) a year.
The majority of these cities are located in the Southern states. Texas has the most cities on this list of hottest U.S. cities, with 16, followed by Florida with eight. Among the other hottest states in the country with numerous cities on our list are Louisiana and Mississippi.
Many of the hottest cities in America are also relatively dense and populous urban areas. As human-made creations such as buildings, roads, and other infrastructure replace natural landscapes, temperatures often rise. The result is what is referred to as a “heat island.” In the evening, the temperature in an urban heat island can be as much as 22 degrees warmer than in nearby rural areas.