Over the course of a playing career that wound through Spain, Mexico and the sun-baked fields of Major League Soccer’s summers, American midfielder Tab Ramos was never hotter than at the 1994 World Cup in the United States.
The day before the United States opened its tournament against Switzerland in the Pontiac Silverdome, it had been 37 degrees in Michigan. By the 11.30am kick-off on matchday, the temperature reached 32 degrees again.
Worse still, the Silverdome was an NFL stadium designed for winter – to keep heat in, rather than out. The first World Cup match played indoors was conducted in a dome without air conditioning. On the field, the temperature reached 41 degrees. The grass laid over the artificial turf had been watered so eagerly that, with the sun beating down on the stadium’s fabric roof, the air turned soupy with humidity.
“We were boiling in there,” Ramos says. “They were carrying people out from the upper deck; fans were passing out.”
The heat was one of the players’ biggest gripes all the way through to the final between Brazil and Italy in Pasadena, California, where it was 38 degrees at kick-off. Fifa was unsympathetic. “Journalists predicted players would die [in Mexico],” a spokesman told the LA Times, pointing to the lack of casualties from the 1986 edition, where it was also hot and the air thin and smoggy, as some kind of perverse validation. “We encourage them to drink water.”
More than three decades on, with the World Cup returning to the United States along with co-hosts Mexico and Canada, the story may be much the same.
Fourteen of the 16 host cities for next summer’s biggest-ever, 48-team, 104-match World Cup are predicted to see afternoon temperatures high enough to endanger the players. So says a study of the 20-year meteorological record published in The International Journal of Biometeorology in January, which urges organisers to avoid afternoon kick-offs.
Nine of the venues will probably experience a wet bulb globe temperature – a measure that combines the effects of the air temperature, humidity, solar radiation and wind speed – above the safety threshold of 28 degrees on more than half the afternoons of hot summers.
The risks will be highest in half a dozen cities with open-air stadiums: East Rutherford, Foxboro, Kansas City, Miami, Monterrey and Philadelphia. (An earlier study, published in October, made a similar prediction, forecasting “very high risk of experiencing severe heat stress conditions” in 10 of 16 venues.)
“The threat of extreme heat will be bigger at this World Cup than it was [at the 2022 World Cup in Qatar],” says Dr Donal Mullan, a climate scientist at Queen’s University in Belfast and the lead author of the most recent study. “Some of these venues are kind of a disaster waiting to happen.”
The 2022 World Cup in Qatar was moved from the scorching summer months to November and December to protect the players. The highest wet bulb temperature – which is slightly different from wet bulb globe temperature – recorded during the World Cup in Qatar was 23 degrees.
Fifa and US Soccer recommend that games implement cooling and hydration breaks when the WBGT exceeds 32 degrees. More cautious governing bodies, like the Australian federation, set a WBGT limit of 28 degrees before matches can be delayed or even postponed.
However, temperatures below those guidelines can still be dangerous. During the 2024 Copa América, held in the United States, an assistant referee collapsed from heat stress during a match in Kansas City when the WBGT was a mere 27½ degrees. A few days earlier, defender Ronald Araujo had to be substituted out of Uruguay’s opening game with Panama in Miami due to dehydration.
When WBGT reaches around 30 degrees, the body’s physiological frailties are exposed. “The weakest link in the chain is going to break first and the heat will bring that about quickly,” says Dr Robert Huggins, a kinesiology professor at the University of Connecticut who worked with the US women’s national team and the Portuguese men’s team to prepare them to play in major tournaments in high heat.
“From a thermoregulation perspective, the hotter the ambient temperature and the higher the humidity, the worse our body can dissipate the heat. If my sweat cannot evaporate off the surface of my skin and be accepted by the environment, I will not be able to physically cool my body.”
Kick-off times have not been announced for the 2026 World Cup yet, and Fifa did not respond to an email asking whether it would consider player safety in scheduling games and avoid afternoon kick-offs at its hottest venues.
“That’s the obvious answer, schedule it outside of these [afternoon] kick-off times,” says Mullan. “If you avoid those afternoon hours between 12 and 6pm, that would make an enormous difference.”
The tournament’s expanded format will make that difficult. For most of the first two rounds of the group stage, there will be four matches a day. During the last round of group stage matches, there will be six games a day. The round of 32 has five days with three scheduled matches. To maximise TV viewership around the world, a good number of those matches will probably have to be played in the afternoon heat.
The study Mullan authored was based on the summer temperatures from 2003 through 2022, which is to say, Mullan points out, that it represents a conservative estimate that did not incorporate the record heat in the summers of 2023 and 2024. Nor, for that matter, does it account for the possibility of wildfire smoke.
Fifpro, the trade union of professional soccer players, has urged Fifa to lower the WBGT temperatures at which cooling breaks are mandated to 26 degrees and set a limit at which games are to be delayed or postponed at 28 degrees. Yet even those measures may not be enough in the eyes of some experts. A paper co-authored by Fifpro’s chief medical officer, Vincent Gouttebarge, questions whether a single cooling break per half is sufficient.
And lowering the threshold at which cooling breaks or delays and postponements kick in may not be enough to protect players and match officials. Dr Glen Kenny, a professor of human and environmental physiology at the University of Ottawa and a world-renowned expert on the links between exercise and heat strain, warns that WBGT limits may prove insufficient to protect players and officials. Because there are, he argues, still too many loose variables that portend risk – like the number of games and training sessions a player has completed in the previous days, and at what temperature.
“I get the idea that we want to be protective,” says Kenny. “You’re trying to come up with a threshold that is all-encompassing, essentially protect everybody – one size fits all. But there will be other factors that may come into play here that are essentially going to limit that person’s ability to thermoregulate.”
After studying the effects of heat strain for decades, Kenny says that it remains difficult to predict how individuals will cope working in dangerously hot conditions, especially if the exposure is sustained over a longer period. Someone playing or practising in the heat for a 14th consecutive day, he argues, will respond differently than they did on the first day. “Even if they hydrate adequately, you will see that the next day the vast majority of them are going to be dehydrated,” Kenny says. “That in itself degrades their capacity to lose heat. So that same threshold may not be relevant on day 14.”
If there was a silver lining to the chaos sowed by pushing the Qatar World Cup to the fall, in the middle of the European club season, it was that players were not yet exhausted by the cumulative strain of a season that runs 10 months or longer. That won’t be the case in 2026.
“If you think of the timing of the World Cup, June and July, it comes at the end of a very challenging season for a lot of the players, playing 50, 55 domestic and continental games,” says Mullan. “A lot of these players are at massive risk as it is.” – Guardian
Leander Schaerlaeckens is at work on a book about the United States men’s national soccer team, out in 2026. He teaches at Marist College.
