Heat caused record-high rates of health emergencies in some parts of the US last year, CDC report shows

Last summer was the hottest ever recorded in the United States, and heat-related health emergencies also reached record-high levels in some parts of the country.

Last summer was the hottest ever recorded in the United States, and heat-related health emergencies also reached record-high levels in some parts of the country. In the United States, the vast majority of emergency department visits for heat-related emergencies — such as heat stroke, heat cramps and sunburns — happen during the warm season that lasts from May through September, peaking in July and August, according to surveillance data collected by the US Centers for Disease Control and Prevention. During the warm season last year, heat-related illnesses accounted for a 20% larger share of emergency department visits than they did in the five previous seasons. Data from hundreds of emergency departments across the country shows that 180 out of every 100,000 total visits were due to heat-related illness in 2023, compared with 151 out of every 100,000 total visits from 2018 to 2022. The risks of peak heat are also becoming more extreme, with the rate of heat-related emergency department visits surging above peaks from previous years and other parts of the same warm season. In July and August of last year, there were more than 300 heat-related emergencies for every 100,000 total emergency department visits, CDC data shows. That’s nearly 50% higher than the average peak rate from 2018 to 2022, and about three times higher than the rate from other warm-season months in the same year. In previous years, risk during the peak heat season was about twice as high as in other warm months in the same year. The US Department of Health and Human Services considers a day to be an extreme heat day if the temperature rises above 95% of the average historical temperatures in that region. The CDC assessed trends in heat-related emergency department visits against a similar threshold. In 2023, all regions of the US experienced at least one day where the rate of heat-related emergency department visits reached an extreme level, topping 95% of rates from 2018 to 2022. In a particular southern region — encompassing Arkansas, Louisiana, New Mexico, Oklahoma and Texas — emergency department visits for heat-related illness reached this extreme level for more than a third of 2023’s warm season, including a period of 16 consecutive days. In four southern regions, comprised of 21 states, 2023 brought more days with extreme rates of emergency department visits for heat-related illness than any other year on record.