Nearly a quarter of matches at the 2026 World Cup could be played in extreme heat conditions driven by climate change, researchers warned on Thursday.
Scientists from the World Weather Attribution (WWA) said rising global temperatures are increasingly calling into question the viability of hosting summer World Cups in the Northern Hemisphere.
Friederike Otto, a researcher at Imperial College London and co-founder of the WWA, said climate change is already reshaping the conditions under which major sporting events are held.
The researchers analysed weather risks for all 104 matches scheduled between 11 June and 19 July 2026 across 16 stadiums in the United States, Canada and Mexico.
According to the study, players and supporters are expected to face far greater exposure to oppressive heat and humidity than during the 1994 World Cup, also hosted in the US.
The analysis relied on the "wet-bulb globe temperature" (WBGT), a heat index combining air temperature, humidity, sunlight and cloud cover to measure how effectively the human body can cool itself outdoors.
Researchers warned that even moderate temperatures can become dangerous when humidity levels are high. A WBGT of 28°C, for example, can correspond to 38°C in dry conditions or around 30°C in highly humid environments.
Out of the 104 matches, around 26 are projected to take place under WBGT conditions of at least 26°C, a threshold at which footballers’ unions recommend additional cooling measures.
An estimated five matches could exceed 28°C WBGT, a level at which player unions have advised that games should be cancelled because of the health risks.
Among the fixtures identified as particularly high-risk are the France versus Senegal match scheduled for 16 June in Miami, as well as matches in Kansas City and New York/New Jersey.
Although some stadiums will be equipped with air conditioning systems, Otto warned that outdoor fan zones and gathering areas could expose supporters to serious heat-related illnesses without adequate medical support.
Reacting to the findings, Simon Stiell, head of the United Nations Framework Convention on Climate Change, called for faster global action to protect both sport and public health from climate risks.
He said accelerating the transition towards clean energy would be essential to limit worsening extreme weather conditions in the future.
