Dangerously Hot and Humid Days Soon Will Become Regular Occurrences

Climate change will make “danger days” — periods when temperature and humidity push the heat index to 105 degrees F or higher — much more common over the next 15 years, according to a Climate Central analysis. Looking at 144 U.S. cities, the team determined that only 12 cities have averaged more than one dangerously hot and humid day per year since 1950. By 2030, though, 85 cities — home to nearly one-third of the U.S. population — will likely experience at least 20 danger days each year. That’s a dramatic and fast-approaching change from current conditions, the analysts note. Houston, for example, saw only three danger days between 2000 and 2010, but it should expect 102 danger days each year by 2050. The most dramatic increases will be seen in the South, the analysis found. Charleston, West Virginia, is expected to become the most dangerously hot and humid city in the country, experiencing 168 danger days per year by mid-century.