Climate scientists are raising serious concerns about dangerous heat conditions at the 2026 FIFA World Cup, warning that roughly one in four of the tournament's 104 matches could be played in conditions that pose a significant health risk to players and fans alike. The warning comes from World Weather Attribution (WWA), a network of climate researchers, whose analysis finds that global warming has substantially increased the extreme heat risk since the United States last hosted the tournament in 1994.

The 2026 World Cup — the largest men's tournament ever staged, featuring 48 national teams across 16 host cities in the United States, Canada and Mexico — runs from 11 June to 19 July. Using the Wet Bulb Globe Temperature (WBGT) index, a heat stress measurement that combines air temperature, humidity, wind and solar radiation, WWA researchers estimate that around 26 of the 104 matches could be played in conditions exceeding 26°C WBGT. At that threshold, the international footballers' union FIFPRO recommends mandatory cooling breaks. More alarmingly, around five matches could exceed 28°C WBGT — a level at which FIFPRO says matches should be delayed or postponed. That risk has nearly doubled compared to equivalent conditions in 1994, with climate change having increased the intensity of extreme heat at host venues by between 0.7 and 1 degree Celsius.

Several host cities, including Dallas, Houston, Miami and Atlanta in the United States, as well as Monterrey in northern Mexico, regularly see temperatures above 30°C during June and July, often combined with high humidity. Of the 16 venues, only three — in Dallas, Houston and Atlanta — have air-conditioned stadiums. The tournament's final, to be held on 19 July at MetLife Stadium in East Rutherford, New Jersey, faces a one-in-eight chance of exceeding 26°C WBGT and a 2.7 percent probability of reaching cancellation-level 28°C conditions. "That the World Cup Final itself — one of the biggest sporting occasions on the planet — faces a non-insignificant risk of being played in 'cancellation-level' heat should be a wake-up call for FIFA," said Friederike Otto, WWA co-founder and climate science professor at Imperial College London.

Scientists emphasise that fans may face even greater risks than players. Spectators can spend hours outdoors travelling to stadiums, queuing and sitting in direct sunlight, without access to the medical support available to athletes. People with pre-existing health conditions are considered especially vulnerable. "It's dangerous for players, but of course there are also the fans who might gather outdoors, and they are at even more risk," Otto said. Simon Stiell, executive secretary of UN Climate Change, added his voice to the concern, stating that the risk of dangerous heat has doubled since 1994 and calling for a faster transition to clean energy.

FIFA says it has contingency plans in place, including real-time monitoring of WBGT and heat index levels, cooling breaks already mandated for each half of matches, and established protocols to respond to extreme weather events. However, scientists stress that institutional preparedness can only go so far when the underlying driver — long-term global warming — continues to intensify. With the tournament less than a month away, researchers say their findings are intended not to be prescriptive but to clearly communicate the scale of risk that organisers, athletes and supporters are likely to face.