Heat waves are occurring in the U.S. more often than they used to
The frequency of heat waves has increased steadily each decade, from an average of two heat waves per year during the 1960s to six per year during the 2010s.
Heat waves are occurring more often than they used to in major cities across the United States. Their frequency has increased steadily, from an average of two heat waves per year during the 1960s to six per year during the 2010s.