Around 25% of the 104 football matches scheduled between June 11 and July 19 in Canada, the United States, and Mexico will be played under extremely hot conditions that could pose health risks to both players and fans, according to a scientific study published by World Weather Attribution.
The extreme heat conditions could make it harder for players and fans to regulate their body temperature, increasing the risk of health complications. Why?
The body can cool itself in high temperatures through processes such as sweating. However, this ability can be limited by environmental factors. The Wet Bulb Globe Temperature (WBGT) index measures the effectiveness of body temperature regulation to understand the risks that heat can pose to people during outdoor activities, especially during physical exercise like football.
The index not only analyzes the daily temperature provided by the national weather service, but also considers direct exposure to solar radiation, humidity and wind conditions in the surrounding environment, and the evaporation rate of sweat.
“A 30°C day in dry, breezy conditions is very different from a 30°C day with high humidity, strong sun and little wind,” consultant anaesthetist at the Imperial College Healthcare NHS Trust, Chris Mullington, explains and adds: “High humidity reduces the evaporation of sweat, limiting the body’s primary cooling mechanism. That is why WBGT is so important”.
When the WBGT exceeds 26°C, the International Federation of Professional Footballers’ Associations (FIFPRO) – which represents players’ unions – call for safety measures, such as breaks every 30 minutes during matches to allow players to cool down and acclimatize. Of the 104 World Cup games, 25% will be played in these conditions, with temperatures above 26°C.
The study reveals that five of the 104 matches will take place in even riskier conditions: the WBGT will exceed 28°C. “Player performance can suffer. The risk of serious
heat illness becomes more concerning”, Mullington explains. Given this second scenario, FIFPRO recommends the match to be delayed or postponed until the well-being of players and fans can be ensured. Will this happen at the next World Cup?
Since the last World Cup was held in the United States in 1994, atmospheric carbon dioxide (CO2) concentrations have risen from 360.94 parts per million (ppm) to 428.62 ppm. This increase is a result of human activities, such as the extraction of fossil fuels and the expansion of intensive agriculture.
Professor of Climate Science at Imperial College London Friederike Otto highlights: “The 1994 World Cup may not feel particularly distant to many adults today, yet half of human-induced climate change has happened since then.”
Messi, Neymar, or the fans: who will suffer the most from the heat?
In the first phase of matches, favorite Lionel Messi and his team will be exposed to less challenging heat conditions than his eternal rival and Brazilian friend Neymar.
The first match of the reigning world champion, Argentina, against Algeria, has a 1 in 7 chance of exceeding 26°C WBGT. In contrast, the climate conditions for Brazil versus Scotland match at the Miami stadium are near certain to surpass those levels.
But it will be the Tunisia vs. Netherlands game in Kansas City that faces the greatest risk: there is a high chance that the 26°C index will be exceeded. Furthermore, this match carries the highest risk of exceeding the 28°C index, meaning that, according to FIFPRO recommendations, the match should be delayed or postponed.
“This is dangerous for players, but there are also the fans who might gather outdoors,” Otto highlights adding: “They are at even more risk, because they will not be taken care of by a lot of doctors.”
On and off the field: what measures should be taken?
Matches played in cities with hotter summers, such as Miami and Kansas City, will kick off at 5, 6, or 7 p.m. to avoid exposure to the highest temperatures of the day. Experts agree that this measure is necessary, but not enough.
One way to mitigate the impact of the heat on players’ health could be to consider a longer interval between halves, or even every 30 minutes as recommended by FIFPRO. This would allow players to hydrate and acclimatize sufficiently to recover their body temperature. However, this measure could also be detrimental to the fans.
“I think it’s about the stuff that you do outside of the stadiums,” Mullington says and shares an example: “Maybe don’t charge for water, maybe offer it for free. Because your average football fan would not pay 8 pounds (10 USD) for a bottle of water. But if they were giving it for free, they would gladly take it.
The expert emphasizes a key element that often goes unnoticed: raising public awareness about the impact extreme heat can have on health. “I don’t think the majority of fans are aware that they might be putting themselves at risk in this situation, so just being transparent about that is important for them to make their own decisions,” he explains.
Miami, Texas, or New York: Which venues will be most affected?
Whether by bad luck or planning error, the World Cup’s most crucial matches will be played in the cities with the highest risk of extreme heat. New York will host the final with a 50% greater risk of heat-related disruption than during the 1994 World Cup, and in a stadium without air conditioning.
New York won’t be the only venue without air conditioning. Miami is another example, where the risk of extreme heat will be high, with several games being played in conditions exceeding recommended limits.
Kansas City and Philadelphia are also included in this trend. In fact, more than a third of the games—including the final, the third-place game, and the quarterfinals—have at least a 1 in 10 chance of exceeding 26°C WBGT and will be played in venues without air conditioning.
Only three of the 16 stadiums will have air conditioning to mitigate heat impact. This is the case in Dallas and Houston, where the risk of exposure will be high. Fans face a 1 in 3 chance of enduring temperatures above 28°C WBGT outside the arena for most matches.
Experts insist that it is not just about what happens during the game, but also before and after, and during daily life during the tournament. “Players and fans have to get to those stadiums and often that will require long periods of time,” Mullington says, adding: “Outside or on crowded public transport, they will be exposed to some risk.”
The popular “Fan Festivals” held outdoors during the World Cup should include safety measures to mitigate the impact of extreme heat on fans’ health.
The 13 matches to be played in Mexican cities and the seven in Canada will face a very different situation. The study reveals that it is almost impossible, or the chances are very low, that extreme heat conditions will occur there. Should these venues have been prioritized when planning the geographical distribution of the cup?
Summer or winter: Should the dates have been changed?
Four years ago, for the first time in its history, the World Cup wasn’t held in June and July, but in November and December. The reason? To avoid the extreme heat of the Qatari summer.
The organizers anticipated that temperatures in Qatar during the summer would be too high for the sport, and the tournament was held during cooler months. Some are wondering if the same measure should have been taken this year.
“Definitely, FIFA needs to think about this very carefully, what would be more sensible times to have these world cups,” Otto analyzed, suggesting holding the event at the beginning or end of the year when located in the Northern Hemisphere
While FIFA President Gianni Infantino acknowledged that heat is a problem, he focused on air-conditioned stadiums to address it.
On the road to the 2026 World Cup and already looking ahead to future tournaments, Mullington emphasized: “The risks (of extreme heat and its impact on health) are only going to increase. When World Cup venues are being decided in the future, climate should be a factor increasingly taken into account.”
