Summary/Abstract
The warmest average temperature recorded since 1850 occurred in 2023. Recent studies have found exposure to extreme heat to be associated with mortality, with variability by age, sex, and race and ethnicity. Recent research suggests that heat-related mortality risk is increasing globally, but formal analyses of heat-related mortality trends in the US through 2023 are lacking. This study examined trends in heat-related mortality rates in the US population from 1999 to 2023, and found that heat-related mortality rates in the US increased in that time period, especially during the last 7 years.