Heat-Related Deaths in the US: Mortality Trends Year After Year

Heat is now the deadliest weather-related hazard in the United States, killing more Americans annually than hurricanes, tornadoes, and floods combined. The year-over-year CDC data behind that statement shows a trend that has accelerated sharply in the last decade.

The recent numbers

CDC mortality data recorded 1,156 heat-related deaths in 2020, climbing to 2,415 in 2023, the highest annual total on record, before easing slightly to 2,394 in 2024. Since 2020, cumulative heat-related deaths in the US have exceeded 9,436. A JAMA analysis of the 1999-2023 period found the death rate had been roughly flat for years before accelerating at close to 17% annually from 2016 onward.

Why the real number is likely higher

CDC researchers and independent analyses consistently note that heat-related deaths are undercounted, since heat is frequently a contributing rather than a listed cause on death certificates, masked by the cardiovascular, respiratory, or kidney failure event it triggers. Excess-mortality studies comparing expected versus observed deaths during heat events tend to find higher tolls than official heat-coded statistics alone.

Who the data shows is at risk

CDC figures show heat-related mortality skews toward men and adults 65 and older, consistent with the classic heat stroke profile. But the data also shows more than one in five heat-related deaths occur in people aged 15 to 44, an age range where exertional heat stroke, tied to sports, occupational exertion, and military or fire service activity, is the more likely mechanism rather than classic heat stroke.

Turning the trend into an operational response

Rising mortality figures are a population-level signal, but the response has to happen at the individual incident level: recognizing exertional heat stroke fast and cooling immediately. The Kollder emergency cooling tub supports that response with solo deployment in under 2 minutes, built for the scenario where minutes determine the outcome. Details at kollder.com/#contact.

Further Reading

• Douglas Casa: Exertional Heat Stroke Is Survivable
• Climate Change and the Rising Frequency of Heat Waves
• Coup de chaleur en France : chiffres de mortalité année après année (FR)
• Request a Kollder Quote

Sources: CDC National Vital Statistics System / CDC WONDER (Heat-Related Deaths, ICD-10 codes X30, T67, P81.0), JAMA, Heat-Related Mortality in the United States 1999-2023, 2024.