Two World Cup matches were played in conditions of severe heat, according to an analysis by the Guardian. The games, held in Miami and Monterrey, reached a heat level that a football players' union had previously warned should trigger delays or postponements.
Heat Conditions at the World Cup
The analysis of the first 24 matches of the tournament found that Saudi Arabia's game against Uruguay in Miami experienced the most severe heat conditions among stadiums without air conditioning. The second most severe was Sweden versus Tunisia in Monterrey. Despite being evening kick-offs, these matches were played with wet-bulb temperatures of 28°C (82°F) or above.
Fifpro, the global players' union, has previously argued that games at or above 28°C should be delayed or postponed. However, the union declined to comment on the heat situation at this World Cup, which is forecast to be the hottest since the tournament began in 1930.
Understanding Wet-Bulb Temperature
Wet-bulb temperature measures heat stress by combining air temperature, humidity, and cloud cover to determine how effectively the human body can cool itself through sweating. Beyond a certain threshold, sweat cannot evaporate, leading to overheating and potential illness or death.
The Guardian used weather data from US and UK government agencies and derived wet-bulb temperatures using a formula employed by authorities in Australia and Canada.
Mitigation Measures
Fifa has implemented measures such as moving kick-off times later in the day and introducing mandatory water breaks. Some venues have roofs or air conditioning to reduce heat. For example, England's match against Croatia in Dallas had a wet-bulb temperature of nearly 35°C (95°F), but air conditioning inside the stadium lowered it to 22°C (71°F).
In total, six of the first 24 matches were held in locations where wet-bulb temperatures hit 28°C or above. These include Germany versus Curacao in Houston, Saudi Arabia versus Uruguay in Miami, Portugal versus DR Congo in Houston, the Netherlands versus Japan in Dallas, and England versus Croatia in Dallas. The Houston stadium also has air conditioning.
Concerns for Fans and Workers
Record-high temperatures have caused fans to struggle in shadeless heat, and there are warnings that stadium workers face hazardous conditions. Fifa's current guidelines recommend cooling breaks at 32°C (89°F) or above, though these have occurred at lower temperatures during the tournament. Delay or suspension of games is at the discretion of organizers.
A group of heat and public health experts urged Fifa in an open letter to implement more extensive heat protections, citing Fifpro's call for potential game cancellations at 28°C or above. Robbie Parks, an environmental epidemiologist at Columbia University and a signatory, noted that temperatures are often taken from shaded areas, and direct sun exposure can be dangerous even at lower temperatures.
Parks emphasized the importance of shade and hydration for fans and workers, suggesting measures like allowing people to bring their own water and using misters for evaporative cooling. He expressed concern about the final in New Jersey, where the stadium is not covered, but hoped Fifa would learn to deal with heat by then.
Broader Impact
Extreme heat is the deadliest hazard worsened by the climate crisis, causing more deaths than hurricanes, floods, and wildfires combined. The World Cup itself contributes to planet-heating pollution, with over 100 matches expected to produce 7.8 million tonnes of greenhouse gases, double the amount of the previous World Cup in Qatar, according to estimates by Greenly.
A Fifa spokesperson stated that the governing body is committed to protecting health and safety, with meteorologists stationed at venues and a tiered mitigation model for extreme temperatures. Measures include mandatory hydration breaks, access to cooling tools, and a medical set-piece protocol for heat exertion, including cooling bags used for the first time. Fifa will continue to monitor conditions and apply contingency protocols if extreme weather occurs.
