The World Health Organization has released new guidance for reducing heat-related illness at mass gatherings, including major sporting, religious and cultural events.
The guidance, published September 30, treats extreme heat not only as an individual health risk but as an operational challenge that can affect crowd movement, medical services, workers, volunteers, transport and local health systems.
What the Evidence Shows
WHO says its evidence review covered studies published between 1980 and 2025 and documented nearly half a million medical encounters at mass gatherings, including more than 22,000 heat-related illnesses.
The review also found that when on-site medical systems are well organized, more than 90% of patients can be treated at the event venue rather than being transferred to hospitals. WHO presents that finding as evidence that preparedness can reduce pressure on local ambulance and hospital services.
Why Mass Gatherings Are Different
Large events can concentrate several heat risks at the same time. People may spend long periods outdoors, stand in dense crowds, travel through unfamiliar climates and have limited access to shade, safe drinking water, cooling or medical care.
Those risks can affect attendees as well as staff and volunteers. WHO also notes that extreme heat can worsen existing health conditions and disrupt normal event operations.
What WHO Recommends
The new guidance emphasizes a combination of measures rather than relying on a single intervention. WHO highlights access to safe drinking water and toilets, cooling infrastructure, schedule adjustments, crowd-flow management, worker protections, public communication, real-time surveillance and prepared on-site medical services.
The agency also published a risk-assessment tool intended to support structured heat-risk evaluation before and during events. The broader framework covers the full event lifecycle: preparation, impact mitigation and recovery.
The Limits of the Guidance
The WHO material is designed as a planning framework, not a universal temperature threshold for cancelling or modifying events. Local climate, humidity, crowd density, venue design, attendee demographics and access to cooling or medical care can all change the level of risk.
The guidance is also intended to complement national heat-health plans, occupational safety rules, clinical guidance and emergency-preparedness systems rather than replace them.
Verified Source Evidence
WHO’s September 30 news release and implementation guidance support the article’s description of heat planning for large events and the whole-of-event risk-management approach.
The guidance focuses on spectators, attendees, volunteers and workers.
