Almost one in five matches at the 2026 FIFA World Cup were played in heat and humidity conditions that a football players' union says should lead to postponements, a Guardian analysis has found. The investigation, published on Wednesday, estimates that 20 of the tournament's 104 fixtures were contested with wet bulb globe temperature (WBGT) readings at or above 28C (82F) — the threshold at which Fifpro argues games must be delayed or called off to protect players' health.
A further 23 matches took place in host cities where ambient heat reached those dangerous levels, but the stadiums' air-conditioning systems mitigated the on-pitch conditions. The data underscores a growing existential challenge for elite sport: how a warming planet is making tournament football increasingly unsafe for athletes and spectators alike.
"The climate crisis is hitting the things we all need, like a stable climate, clean air and affordable food, as well as the things we love, like football and other sports," said Simon Stiell, executive secretary for the United Nations climate body, in an emailed comment to The Guardian.
A 'stress test' for football's future
The findings are the starkest illustration yet of how climate extremes are reshaping the sport's calendar. The World Cup itself was already shifted from its traditional June-July slot in 2022, when Qatar hosted in November and December. For 2026, the tournament reverted to its summer window across the United States, Mexico and Canada — a period during which large swathes of North America are now in the grip of record-breaking heatwaves.
On the day the Guardian analysis was published, more than 125 million Americans were under dangerous heat alerts stretching from California to New England. The World Cup final on Sunday between Argentina and Spain at MetLife Stadium in New Jersey is forecast to have a WBGT reading just below the 28C threshold at around 26C (79F), with low humidity providing some relief. However, a secondary climate threat looms: wildfire smoke from ongoing blazes is expected to degrade air quality in the region, with New York City mayor Zohran Mamdani already warning of health impacts for residents and visitors.
"The 2026 FIFA World Cup matches have introduced a true stress test of heat mitigation and preparedness," said Joshua L DeVincenzo, assistant director at Columbia University's National Center for Disaster Preparedness. "FIFA, spectators, stadium operators, and others … were tested firsthand on the disruptions and complications that extreme heat and weather can pose."
Player welfare measures and unanswered questions
FIFA has not responded to The Guardian's request for comment on the fresh analysis. The governing body previously stated that it stationed meteorologists at match venues to monitor conditions and that tournament planning involved "close coordination" with host city organisers, stadium authorities and national agencies. Players were granted mandatory hydration breaks and given access to water, electrolyte drinks, ice, cold towels, fans, mist and shade during matches.
Yet the reliance on such ad-hoc cooling measures, rather than schedule changes, is seen by many as inadequate. Fifpro declined to comment on the new study but has previously told the Guardian: "The lesson for everyone in the industry is that with a warming planet, heat conditions will play a bigger part in tournament and league scheduling decisions in the future."
The Guardian's analysis compiled WBGT approximations based on air temperature and humidity data because official on-site readings require specialised equipment. The figure of 28C WBGT — a measurement that accounts for humidity, sunlight and wind to gauge heat stress — is the point beyond which the human body cannot effectively cool itself through sweating. At sustained high levels, the risk of heat illness or death escalates rapidly.
Broader implications for football
The 2026 World Cup is now being viewed as a watershed moment for the sport's relationship with climate change. The tournament was already under fire for the enormous carbon footprint of a 48-team event spread across a continent. The fresh evidence of dangerously high on-field temperatures may force governing bodies to consider more radical interventions — from time-of-year shifts for future editions to stricter game-delay protocols and mandatory stadium climate-control standards.
For now, the focus turns to Sunday's showpiece final, where Argentina and Spain will compete for the trophy under skies that threaten not just heat but smoke. The match offers a stage upon which football's climate reckoning will play out in real time, with hundreds of millions watching as the world's most popular sport confronts an increasingly inhospitable environment.