Rising Temperatures: The Growing Prevalence of 100-Degree Days in Urban Centers

The United States has seen increasingly scorching summer days. According to data from airport weather stations collected by the National Oceanic and Atmospheric Administration during the past 75 years, days with highs over 100 degrees Fahrenheit have become more frequent in the 25 major US cities.

This year is no different. According to NOAA, the number of triple-digit highs during the first seven months of 2023 was the sixth-highest since 1948 in the 25 major cities for which statistics were available. The number of days in July that exceeded 100 degrees Fahrenheit in 2016 was at its highest level in 75 years.

According to experts, the climate issue is causing heat waves to be more intense and to cause days that would typically reach highs in the triple digits. The infrastructure of a city is put under greater stress as the frequency of days with excessive heat rises. This is especially true for those who work outside or don’t have access to proper shelter.

Heatwaves in Cities

“Climate change has already occurred. Since at least 150 years ago, greenhouse gas levels have increased, according to David Easterling, director of NOAA’s National Centers for Environmental Information’s Climate Assessments Section. And that means that it’s becoming warmer everywhere, whether in Phoenix or Las Vegas.

Over the previous 20 years, residents of the 25 major cities have endured three more yearly days over 100 degrees than they did between 1948 and 1980. According to NOAA, the average number of days with triple-digit temperatures increased between those two times in 17 of the 25 major US cities with data available.

The amount by which triple-digit hot days have increased in frequency varies greatly throughout the nation. Since 2003, Portland, Oregon, has seen an average of more days per year with temperatures exceeding 100 degrees than it did between 1948 and 1980. Phoenix, on the other hand, averages 18 more days with temperatures in the triple digits between those same two times.

Source: CNN