Much of the United States is currently in the midst of a brutal heat wave that could bring record-breaking temperatures to several cities in the Northeast and Midwest. Chicago reached 103 degrees Fahrenheit on Sunday, the hottest Father’s Day in the city since 1995. A handful of other Midwestern cities broke heat records on Sunday, and New York City, Boston, and Washington, D.C. are on track to do the same this week.
Hot weather can exacerbate the formation of ground-level ozone, which can be particularly harmful to children, the elderly, and individuals with respiratory illnesses. Environmental agencies have issued a Code Orange air quality alert in parts of the Northeast and Mid-Atlantic.
While 100-degree weather is a rarity for much of the country, there are a handful of large cities that experience triple-digit temperatures on a regular basis. To identify the 50 hottest cities, 24/7 Wall St. ranked cities based on the average number of 90-plus degree days per year using climate data from the National Oceanic Atmospheric Administration. There are 50 large cities with populations of at least 10,000 where the temperature reaches at least 90 degrees Fahrenheit for more than 67 days in an average year.