Methodology:

To determine the hottest cities in America, 24/7 Wall St. ranked 192 cities based on the average number of 90-plus degree days per year, using climate data from the National Oceanic Atmospheric Administration’s 2018 Comparative Climatic Data report. In cases where multiple cities had the same amount of 90-plus degree days per year, the city with the higher average daily maximum temperature during its hottest month was given the higher rank. Only cities with populations of at least 10,000 were considered.

Averages for each city were calculated since each city began keeping records.

The normal mid-summer high temperature is the 30-year average daily maximum temperature for the month with the highest average daily temperature for each city, using data recorded between 1981 and 2010. The normal year-round high temperature is the 30-year average daily maximum temperature from 1981 to 2010. Highest temperature on record refers to the highest temperature recorded at each city’s weather station, and this figure may differ from citywide or statewide figures. A full year’s data was not always available for the first year listed in each city’s range of recorded temperatures.