The World Health Organisation (WHO) has warned that extreme summer heat is no longer an occasional weather condition but “a permanent public health crisis” in Europe, with young children, pregnant women, and people with chronic conditions at risk.

The WHO described severe heat as a critical public health issue exacerbated by climate change in a statement on Heat Action Day, commemorated globally on June 2 to raise awareness of the risks of heat.

“No longer just an exceptional seasonal phenomenon, extreme summer heat is a critical public health issue amplified by climate change.

“Not just an inconvenience, it is a silent threat that can affect health, strain infrastructure, overwhelm hospitals, cause suffering, and claim lives,” it said.

The global health body said that though the entire population might be affected, the impact of extreme heat varies and older people, outdoor workers, and those in mass gatherings were also at risk.

It said tourists, athletes, refugees, and migrants with inadequate housing were also exposed to risks posed by extreme heat.

The WHO emphasised the importance of countries’ “comprehensive and systemic approach to preparation and response” to heatwaves as summer draws near.

The organisation said its regional office for Europe will launch guidance on heat–health action plans (HHAPs) on June 11 to help governments plan for extreme heat during summer.

It recommended developing HHAPs to help countries prepare for, respond to, and mitigate heat-related health risks, noting that some countries had already implemented such plans.

“However, several countries still have no plans in place, leaving their people and health systems at risk,” it said.

The organisation called for increased public awareness and protective behaviours to reduce the adverse effects of extreme heat.

It cautioned the public against strenuous activity, leaving minors and adults in parked vehicles during the hottest time of the day, and consuming sugary, alcoholic, or caffeinated drinks.

The health body urged increased water intake, spending time in cool environments, reducing indoor heat exposure, and wearing loose-fitting, light clothing.

“People at increased risk of threats to health from extreme heat might need assistance on hot days. If anyone you know is at risk, help them to get advice and support,” it appealed to the public.

With global temperatures rising, extreme heat driven by climate change has become a major health challenge in parts of Europe, as health experts warn that vulnerable groups are at risk.

Last month, the Pan-European Commission on Climate and Health called for climate change to be treated as a public health emergency.

The commission urged heads of government to prioritise funding for climate action, which it described as a primary security risk.

In 2023, the WHO Regional Director for Europe, Hans Henri P. Kluge, declared the climate crisis and extreme weather a public health emergency.

In 2024, the United Nations Secretary-General António Guterres issued a “Call to action on extreme heat” to increase protection for vulnerable populations.