A group of leading international scientists has warned that FIFA’s current heat safety measures for the 2026 World Cup are inadequate and could expose players to serious health risks during the tournament scheduled to be hosted by the United States, Canada and Mexico.
In an open letter signed by 20 experts in health, climate science and sports performance from the United Kingdom, United States, Canada, Australia and Europe, the scientists described FIFA’s existing guidelines as “impossible to justify” based on current scientific evidence and urged the football governing body to urgently strengthen its player protection measures.
The experts called for longer cooling breaks, clearer protocols for delaying or postponing matches in extreme heat, improved cooling facilities for players and regular updates to FIFA’s heat guidelines in line with evolving scientific evidence.
They also urged FIFA to adopt standards proposed by global players’ union, Fifpro.
Heat is expected to pose a major challenge during the tournament, with researchers warning that temperatures at 14 of the 16 stadiums selected for the competition could exceed dangerous levels.
In parts of the southern United States and northern Mexico, average daytime temperatures are expected to remain in the low to mid-30 degrees Celsius, with some areas likely to approach 40 degrees during severe heat periods.
Scientists warned that when humidity, sunlight and wind speed are added to the equation, players would face extreme levels of heat stress capable of causing serious medical emergencies.
Although FIFA has maintained that it is “committed to protecting the health and safety of players, referees, fans, volunteers and staff,” critics argue that the governing body’s existing measures remain insufficient.
As part of its player welfare strategy, FIFA has introduced mandatory three-minute cooling breaks in each half of every match and climate-controlled benches for substitutes and technical staff at outdoor venues.
FIFA also uses the Wet Bulb Globe Temperature (WBGT) system, regarded as the gold-standard method for measuring heat stress in sport. A WBGT reading of around 28 degrees Celsius is widely considered a dangerous threshold for elite athletes.
According to FIFA’s emergency care manual, if the WBGT reading is near, at or above 32 degrees Celsius, match organisers should determine “what precautions need to be taken to prevent any heat-related illness from occurring”.
The scientists, however, argued that those measures do not adequately protect players from potentially dangerous heat exposure.
Andrew Simms, director of the New Weather Institute and coordinator of the letter, warned that overheating could quickly become life-threatening during matches.
“Player safety is an immediate and urgent concern because things can go wrong very quickly when people overheat.
“We’re worried that FIFA is playing recklessly with the health and safety of players,” he said.
Another signatory to the letter, Professor Douglas Casa of the University of Connecticut, criticised the current cooling protocols adopted by FIFA.
“The hydration break in each half absolutely needs to be longer than three minutes – at least five minutes for each break and preferably six.
“We hope this open letter convinces FIFA to update its heat guidelines before the World Cup,” he said.
Fresh analysis conducted by the World Weather Attribution group showed that about a quarter of the matches at the 2026 World Cup are likely to be played above 26C WBGT, while approximately five games could exceed 28C WBGT, a threshold considered unsafe for football by Fifpro.
Researchers also noted that climate change has nearly doubled the likelihood of extreme heat conditions compared to the 1994 World Cup, which was also hosted in North America.
In response to the concerns raised by the scientists, FIFA said it would implement a “tiered heat mitigation model” during the tournament, with safety measures adjusted according to real-time weather conditions.
A FIFA spokesperson said dedicated meteorological support teams would monitor WBGT and heat index readings throughout the competition, while kick-off times had been designed to minimise exposure to extreme temperatures.
The spokesperson added that matches expected to face hotter conditions would, where possible, be prioritised for covered stadiums, while the overall schedule was also structured to minimise travel and maximise recovery periods for teams.
FIFA further stated that it would continue monitoring conditions throughout the tournament and apply contingency measures where necessary in collaboration with host authorities and medical experts to ensure a “safe and resilient” competition.
