Rising global temperatures are directly disrupting international football tournaments.
An analysis by The Guardian found that nearly one in five of the tournament's 100-plus matches occurred under heat and humidity levels that should prompt delays or postponements according to player union standards.
An additional 23 matches took place in cities experiencing severe heat, though conditions were mitigated inside venues by stadium air conditioning.
Climate Crisis Hits Football
"The climate crisis is hitting the things we all need, like a stable climate, clean air and affordable food, as well as the things we love, like football and other sports," said Simon Stiell, executive secretary of the United Nations climate body.
The evaluation examined environmental conditions of 104 matches, including completed games and forecasts for final fixtures.
This shift presents broader structural challenges for football as intense heat waves become more frequent, threatening athlete and fan safety.
"The 2026 Fifa World Cup matches have introduced a true stress test of heat mitigation and preparedness," said Joshua L DeVincenzo, assistant director at Columbia University's National Center for Disaster Preparedness.
"Fifa, spectators, stadium operators, and others were tested firsthand on the disruptions and complications that extreme heat and weather can pose."
The findings emerged during a record-breaking heat wave across the United States, placing over 125 million Americans under dangerous heat alerts.
An estimated 20 matches were played where the wet bulb globe temperature (WBGT) reached or exceeded 28C (82F).
The players' union Fifpro previously argued that matches should be delayed under such conditions. DeVincenzo noted that other attendees also face significant vulnerabilities.
"We learned from this World Cup that, in addition to player safety and health, important precautions must be considered for spectators, volunteers, and stadium staff long before the day of the match," DeVincenzo said.
Fifa did not respond to requests for comment but previously stated that meteorologists were stationed at venues to coordinate with local host cities and national agencies.
Mandatory hydration breaks were enforced, providing water, electrolyte drinks, ice, cold towels, fans, mist, and shade.
Fifpro declined to comment on the latest analysis but previously stated: "The lesson for everyone in the industry is that with a warming planet, heat conditions will play a bigger part in tournament and league scheduling decisions in the future."
Hottest Matches and Future Risks
WBGT metrics combine humidity, direct sunlight, and wind to measure heat stress.
When these factors peak, sweat cannot evaporate efficiently, causing rapid overheating that can lead to severe heat illness.
The hottest match in a non-air-conditioned venue occurred on the Fourth of July during the France v Paraguay round of 16 fixture in Philadelphia.
Temperatures at Lincoln Financial Field reached 38C (100F), with WBGT potentially exceeding 33.9C (93F).
The highest overall temperatures were recorded on 22 June in Dallas, Texas, during Argentina's 2-0 victory over Austria.
Although the game took place in an air-conditioned stadium, surrounding asphalt reached 50C (122F).
DeVincenzo emphasized that more measures must protect people entering venues, exiting matches, or visiting fan festivals.
"Spectator experiences created a secondary risk in the heat; factors such as long walking distances without cover, unshaded areas, sun-exposed seating, and long wait times in heat-emitting spaces like parking lots put people at a much higher risk of heat stress and related injuries."
"These experiences can be addressed ahead of future games by training volunteers to identify signs of heat stress and to know the appropriate actions to take when fans experience dizziness, fainting, or falls," he said.
Every match scheduled in Dallas, Houston, and Miami appeared to breach the 33.9C (93F) threshold.
At Miami's non-air-conditioned Hard Rock Stadium, WBGT readings reached approximately 32.5C (90.5F) during the Norway v England match.
Future international tournaments are expected to face similar climate obstacles. The 2030 World Cup will be hosted across Spain, Portugal, and Morocco, regions already experiencing extreme heat.
Saudi Arabia is expected to host the 2034 tournament during the northern hemisphere winter to avoid summer temperatures that routinely surpass 40C (104F).
