WHO Heat Guidance for Mass Gatherings: What Organizers and Attendees Should Know

Geneva, 1 October 2026. The World Health Organization issued new guidance on 30 September for preventing and managing heat illness at large sporting, religious and cultural gatherings. Its message is practical: organizers should plan for heat across the whole event, from venue design and scheduling to drinking water, medical teams and communication. The guidance addresses a growing operational risk, rather than announcing that any particular forthcoming event is unsafe.

Key points

• WHO says heat illness at mass gatherings can often be prevented or treated on site with timely preparation.
• The advice covers attendees, volunteers and workers, as well as emergency services.
• Water, cooling, schedules, crowd movement and on-site care all form part of the response.

What the evidence says

In its 30 September release, WHO says an evidence review of studies from 1980 to 2025 identified nearly half a million medical encounters at mass gatherings, including more than 22,000 heat-related illnesses. Studies reviewed also indicated that well-organized on-site medical systems could treat more than 90% of patients at the venue. Those are findings across studies, not a promise that every event will achieve the same result.

Large crowds can create risks beyond the day's forecast temperature. People may wait for hours outdoors, have limited access to water or shade, and struggle to move through congested entrances. Visitors may be unfamiliar with local conditions. Workers and volunteers can have prolonged exposure while still performing demanding tasks. A plan focused only on telling individuals to drink water misses these structural factors.

Planning before the event

WHO recommends combining measures. Organizers can provide safe water and toilets, identify cooling spaces, adjust event times, manage crowd flow, protect staff and establish clear health messages. They can also watch conditions and illness reports in real time, with trained medical teams ready to respond. The exact mix should reflect the event, venue, climate and people attending.

Weather forecasts are useful, but planning cannot end with a single temperature threshold. Humidity, direct sun, duration of exposure and access to relief can change the danger. The aim is to make safer choices possible for everyone, including people who may have difficulty finding water, shelter or medical help in a dense crowd. The implementation guidance is intended to support authorities and event operators throughout preparation, operations and recovery.

Why this matters to attendees

For the public, the most useful information is event-specific: where water and cooling areas are, how to obtain medical help, whether schedules have changed and what official alerts say. Symptoms of heat illness can vary; anyone feeling unwell should seek assistance promptly. The guidance is also a reminder that the safety of an event depends on the organizer's systems as much as the choices of individual visitors.

WHO says its new materials complement existing heat-health action plans, occupational safety requirements and emergency arrangements. They do not replace local medical advice or emergency instructions. As more cities host large outdoor events in hot conditions, the test will be whether organizers turn the guidance into visible services and timely decisions on the ground.

Sources: WHO news release, 30 September 2026; WHO implementation guidance.