The 2026 Fifa World Cup is the biggest ever edition of the world’s most watched sporting tournament. The 48 teams taking part in Canada, the US and Mexico may find their toughest opponent is the extreme heat.
Very hot temperatures are expected across many of the states including Texas, California and Florida where World Cup games are being held this summer, with wildfire risks being highlighted in some states. The tournament kicks off on June 11.
The problems heat causes during matches were visible during the 2025 Fifa Club World Cup, played in the same summer months and across many of the same North American venues. Players and managers repeatedly referenced the stifling weather conditions.
Borussia Dortmund manager Niko Kovač said after a match in Cincinnati he was “sweating like I’ve just come out of a sauna”. Chelsea midfielder Enzo Fernández described conditions as “very dangerous”, adding that “everything becomes very slow”. Juventus manager Igor Tudor revealed that ten players asked to be substituted during a match against Real Madrid in Miami, where temperatures reached 30°C, with 70% humidity.
North America’s last World Cup (USA 1994) also produced memorable scenes relating to heat. German striker Jürgen Klinsmann recalled: “I played in Dallas at 120 degrees [49°C ] I was dying” in a match against South Korea. Meanwhile, Republic of Ireland manager Jack Charlton was reprimanded by Fifa officials for throwing water bottles onto the pitch to help his dehydrated players during a game in Orlando.
Extreme heat is not just uncomfortable – it threatens both health and performance. Football already has documented cases of heat-related fatigue, collapses and hospitalisations, including Guatemalan referee Humberto Panjoj collapsing during a 2024 Copa América match in Kansas City.
Heat also changes the game itself. Studies show players cover less distance, perform fewer high-intensity sprints and get tired more quickly in extreme conditions. Tired players are more prone to mistakes and injuries, while hotter matches have been linked to more penalty shootouts, as exhausted teams struggle to break each other down in extra time.
Scientists commonly use Wet Bulb Globe Temperature (WGBT) to assess heat stress. Unlike air temperature alone, WBGT combines temperature, humidity, solar radiation and wind, making it a better indicator of how dangerous conditions feel to the human body.
Several football governing bodies – including the global players’ union Fifpro – consider a WBGT above 28°C to be a threshold where matches should potentially be delayed or postponed.
20-year average levels of extreme heat in 16 venue cities
Author, CC BY
Possible solutions?
A study I led in 2025 found that 14 of the 16 upcoming World Cup host cities are likely to exceed the extreme 28°C WBGT threshold if conditions this summer are typical. Most of the danger falls during mid-afternoon, and Fifa has clearly tried to reduce some of the risk through scheduling. Compared with the Club World Cup, matches in the hottest cities and non-air-conditioned stadiums have largely been shifted away from the most dangerous hours of the day.
That will help – but it will not eliminate the problem.
Some high-risk fixtures remain. Late afternoon (5pm) and early evening (6pm) matches in Miami and Kansas City carry a greater than 30% risk of WBGTs exceeding 28°C if summer temperatures are typical, rising above 50% if conditions are hotter than average. The final at MetLife Stadium in New Jersey kicks off at 3pm, when the probability of extreme heat is about 30% in a typical summer and 55% in a hot one.
Those estimates may even turn out to be conservative. Heatwaves are becoming more frequent and intense globally. The 2021 western North America heatwave shattered records by more than 4°C in some locations. A similarly extreme event during the World Cup could push lower-risk cities such as Seattle, Toronto and Vancouver into dangerous territory, while prolonging extreme evening heat in more vulnerable venues such as Miami, Kansas City and Philadelphia.
And even air-conditioned stadiums do not remove the wider public-health risk.
In the hottest cities such as Dallas and Houston, indoor venues may protect players and match officials during the game itself. But tens of thousands of spectators will still spend hours travelling, queueing and celebrating in dangerous outdoor heat. Many fans are older, less physically fit than elite athletes, dehydrated from alcohol consumption, or arriving from cooler climates with little acclimatisation.
The risk therefore extends well beyond the pitch.
Yet Fifa’s current heat policy remains limited. All matches will have three-minute hydration breaks midway through each half, but the threshold for stronger action remains exceedingly high. Current Fifa guidance only mandates additional precautions at a WBGT of 32°C.
That figure has alarmed scientists and medical experts who have sent an open letter urging Fifa to strengthen its heat protections before the tournament begins. Their recommendations include doubling the time for cooling breaks to six minutes, lowering the WBGT threshold for intervention and introducing clearer rules for delaying or postponing matches in dangerous conditions.
It is possible matches could be delayed or postponed if WBGTs exceed 32°C. This would be a decision for Fifa – and is something they have never done before. It is worth noting that the 32°C threshold is also considerably above levels many experts consider dangerous.
It’s likely that more World Cups will be played outside the traditional summer months in future. This was the case for the Qatar World Cup in 2022, moving from June/July to November/December and is almost certain to be the case for the 2034 tournament in Saudi Arabia.
The 2026 World Cup may ultimately become a defining test for how global sport adapts in a warming world. Scheduling matches outside the hottest hours is a sensible start. But as temperatures continue to rise, timing alone may no longer be enough.
