Higher nighttime temperatures are linked to shorter sleep times and lower sleep quality, especially for people with chronic health conditions, lower socioeconomic status, or those living on the West Coast, according to a new USC study. Researchers estimate that by 2099, people could lose up to 24 hours of sleep each year due to heat, highlighting the potential impact of climate change on sleep health. The researchers obtained data from 14,232 U.S. adults in the All of Us Research Program that was collected between 2010 and 2022. In total, the researchers analyzed more than 12 million nights of sleep, looking at how long people slept and how easily they fell asleep. They also examined 8 million nights of data on sleep stages and how often sleep was interrupted. Finally, they used location and meteorological data to find out whether sleep patterns were linked to changing temperatures. They found that a 10-degree Celsius increase in daytime temperature was associated with 2.19 minutes of lost sleep, while a 10-degree nighttime temperature increase was associated with a loss of 2.63 minutes. The effects were greater among females, people of Hispanic ethnicity, people with chronic diseases, and those with a lower socioeconomic status. In addition to shorter sleep times, rising temperatures were also associated with more disrupted sleep throughout the night and more time spent awake in bed.