FIFA World Cup 2026 promises to be the biggest football festival in history with 48 teams competing. However, in Canada, the US and Mexico, players may face an "invisible" but harsh opponent: Extreme heat. With temperatures forecast to cover states from Texas to Florida, the tournament starting on June 11 is posing unprecedented challenges in terms of health and performance.
Like "breathing
Weather warnings were clearly revealed at the 2025 FIFA Club World Cup, where many complaints about suffocating conditions were voiced. Dortmund coach Niko Kovac compared it to "a feeling of getting wet as if just stepping out of a sauna", while Chelsea midfielder Enzo Fernandez described the "very dangerous" playing conditions as slowing things down. In Miami, 10 Juventus players had to ask for substitutions due to exhaustion under 30 degrees Celsius and 70% humidity in the match against Real Madrid.
32 years ago, the 1994 World Cup in the US also witnessed unforgettable memories of weather. Jurgen Klinsmann shared the feeling of "like dying" when playing in Dallas with 490C, or Irish coach Jack Charlton being criticized by FIFA for throwing a water bottle into the field when players lost water in Orlando. Extreme heat not only causes discomfort but also directly threatens health and performance. There are cases of exhaustion, fainting and hospitalization due to heat, including referee Humberto Panjoj who collapsed in a match at Copa América 2024 in Kansas City.
Under the heat, football is deformed. Studies show that players move less, accelerate less and make more mistakes. Fatigue makes matches sluggish, prolongs time and easily leads to penalty shootouts due to physical exhaustion.
Warning and adjustment
Scientists use the Wet Globe Temperature Index (WBGT) to evaluate. Unlike conventional thermometers, WBGT measures temperature, humidity, heat radiation and wind. The World Federation of Football Players (Fifpro) once warned that the 280C WBGT threshold is a "red line" that needs to be postponed or reversed. A 2025 study shows that 14 out of 16 World Cup 2026 host cities are at risk of exceeding this threshold. Although FIFA has adjusted the schedule, risks still exist, especially late afternoon matches in Miami or Kansas City.
Although some modern stadiums have air conditioning systems, risks still surround tens of thousands of spectators. They are the ones who have to queue, move in the sun and do not have the physiological adaptation like athletes.
Currently, FIFA's protection policy is still considered restrictive. The 3-minute drinking break is not enough and the intervention threshold at WBGT 320C is assessed by medical experts as too high and dangerous. An open letter from the scientific community urged FIFA to lower the intervention threshold, double the cooling break time and have clearer match postponement rules. It should be noted that the 320C threshold is also significantly higher than the level that many experts consider dangerous. It is possible that many future World Cups will be held outside of the traditional summer months. This happened with the 2022 World Cup in Qatar (transicted from July-July to November-December) and is almost certain to happen with the 2034 tournament in Saudi Arabia.
Almost all stadiums hosting the 2026 World Cup are currently recording more extreme hot days during the tournament (July-July) compared to the first World Cup in North America in 1970. The frequency of extreme hot days in July-July has tripled, averaging over 10 cities hosting many times since they hosted the previous tournament in 1986 (in Mexico) and 1994 (in the US).
