GENEVA — Extreme heat threatened the health of millions of people across multiple regions on Saturday as authorities issued warnings, expanded emergency measures and urged residents to limit outdoor activity amid prolonged periods of unusually high temperatures.
Large parts of the United States remained under heat advisories, watches or warnings as a persistent high-pressure system drove temperatures well above seasonal averages, with forecasters warning that daytime highs and unusually warm nights would significantly increase the risk of heat-related illness. The U.S. National Weather Service said dangerous conditions were expected to persist across broad areas of the country, particularly affecting older adults, young children, outdoor workers and people without reliable access to cooling.
In Europe, the World Health Organization's Regional Office for Europe warned that further extreme heat episodes were likely in the coming weeks after recent heatwaves strained health systems across several countries. WHO Regional Director Dr. Hans Henri P. Kluge said governments were treating extreme heat as "a public health emergency, not just a weather event," while calling for stronger coordination, expanded cooling facilities and better protection for vulnerable populations.
Health authorities said older people, infants, individuals with chronic illnesses, pregnant women, homeless people and those working outdoors faced the greatest risks during prolonged periods of extreme heat. The WHO said heat stress remains one of the leading weather-related causes of death worldwide and warned that consecutive hot days and nights reduce the body's ability to recover, increasing the likelihood of heat exhaustion and heatstroke.
Meteorologists in the United States forecast temperatures ranging from 15 to 25 degrees Fahrenheit (8 to 14 degrees Celsius) above normal in some areas, with numerous locations expected to challenge daily temperature records. Officials urged residents to remain hydrated, seek air-conditioned spaces and check on neighbors who may be especially vulnerable.
Across Europe, several countries continued operating heat-health action plans that include public cooling centers, emergency medical coordination and targeted outreach to at-risk populations. WHO officials said lessons from recent heatwaves would be shared among member states to strengthen preparedness before additional periods of extreme heat forecast later this summer.
According to the WHO, climate change is increasing the frequency, intensity and duration of heatwaves globally. The agency estimates that approximately 489,000 heat-related deaths occur worldwide each year on average and says many fatalities can be prevented through early warning systems, public health planning and community preparedness.
Authorities in affected regions said heat alerts and public health advisories would remain in effect where dangerous temperatures were forecast to continue, while emergency services monitored conditions and urged the public to follow official guidance.
