Temperature Extremes

What to know

Extreme heat events are becoming more frequent and intense. Deaths result from heat stroke and related conditions, but also from cardiovascular disease, respiratory disease, and cerebrovascular disease.

Young boy, holding a cap and wiping his brow.

Heat events in the U.S.

Extreme heat events have long threatened public health in the United States. Many cities, including St. Louis, Philadelphia, Chicago, and Cincinnati, have suffered dramatic increases in death rates during heat waves. Deaths result from heat stroke and related conditions, but also from cardiovascular disease, respiratory disease, and cerebrovascular disease.

Heat waves are also associated with increased hospital admissions for cardiovascular, kidney, and respiratory disorders. Extreme summer heat is increasing in the United States. Climate projections indicate that extreme heat events will be more frequent and intense in coming decades.

Heat-related illness

Improved forecasting, early warnings, and increased air conditioning access may contribute to recent reductions in heat-related illness and death risks. However, extreme heat events remain a cause of preventable death nationwide. Urban heat islands, along with aging and urbanization, will likely heighten urban populations' vulnerability to future heat-related health impacts.

Milder winters resulting from a warming climate can reduce illness, injuries, and deaths associated with cold and snow. Vulnerability to winter weather depends on many non-climate factors, including housing, age, and baseline health. Climate change may reduce deaths and injuries from extreme cold, but it won't offset the rise in heat-related deaths.

Watch a short video about climate-related health effects from extreme heat, and what communities can do to prepare.

Resources