The global average temperature has risen markedly since 1980, with 2024 the first year to be more than 1.5C above the pre-industrial average.
The previous World Cup – held in Qatar in 2022 – was moved from June and July, when temperatures regularly exceed 40C and can reach 50C in Doha, to November and December in order to protect players and fans.
The report says the 2026 tournament risks seeing games played at “the level beyond which some football governing bodies recommend match delay or postponement”.
The heat policy of Football Australia, for example, states a match may be delayed or postponed when the WBGT reaches 28C.
However, Fifa’s guidelines say mandatory cooling breaks are provided in each half as a mitigation strategy, with a delay or postponement at the discretion of match organisers.
World players’ union Fifpro, external believes Fifa’s guidelines “do not do enough to protect the health and performance of players”.
It recommends cooling breaks when the WBGT is between 28C and 32C, and for games to be rescheduled above 32C.
The result of playing in such conditions range from small performance-impacting issues such as sleep disruption and late changes to event timings, to severe health impacts such as heat-related stress and injury.
It is not just players who can be affected. During last year’s Copa America, Guatemalan assistant referee Humberto Panjoj had to be withdrawn, external from a game in Kansas City after collapsing on the field when the WBGT was calculated to be 27.5C.
Dr Mullan says Miami and Monterrey “could pose the greatest risk” as they do not have air-conditioned stadiums.
The report suggests afternoon games be avoided in Kansas City, Boston, New York and Philadelphia too.
Although the hottest two host cities – Dallas and Houston – do have air conditioning, there is still a risk to spectators if games are played in the afternoon, Dr Mullan said.
“They will go back out into the soaring heat so there’s a risk for spectators as well as the players and match officials,” he added.
The research findings have been published in The International Journal of Biometeorology., external
