A group of climate scientists has written an open letter to FIFA warning that current heat-related protections for players at the 2026 World Cup are "inadequate."
The World Cup will take place in the United States, Mexico and Canada between June 11 and July 19 – typically some of the hottest weeks of the year.
FIFA has introduced mandatory hydration breaks midway through the first and second half of every World Cup match, but in their letter, the scientists warned that wasn't enough.
"We are concerned that FIFA’s current guidelines on heat stress mitigation are inadequate and will place players at risk of heat injury at the 2026 men’s World Cup," the letter said.
MetLife Stadium – East Rutherford, New Jersey (hosting World Cup final)
AT&T Stadium – Arlington, Texas
Mercedes-Benz Stadium – Atlanta
Arrowhead Stadium – Kansas City
Estadio BBVA – Monterrey, Mexico
Estadio Akron –Guadalajara, Mexico
BMO Field – Toronto
SoFi Stadium – Inglewood, California
BC Place – Vancouver, Canada
Hard Rock Stadium – Miami Gardens, Florida
Lumen Field – Seattle
NRG Stadium – Houston
Levi’s Stadium – Santa Clara, California
Lincoln Financial Field – Philadelphia
Gillette Stadium – Foxborough, Massachusetts
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What stadiums are hosting the 2026 World Cup in North America? See all 16
MetLife Stadium – East Rutherford, New Jersey (hosting World Cup final)
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What stadiums are hosting the 2026 World Cup in North America? See all 16
MetLife Stadium – East Rutherford, New Jersey (hosting World Cup final)
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What stadiums are hosting the 2026 World Cup in North America? See all 16
AT&T Stadium – Arlington, Texas
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Mercedes-Benz Stadium – Atlanta
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Arrowhead Stadium – Kansas City
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Estadio BBVA – Monterrey, Mexico
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Estadio Akron –Guadalajara, Mexico
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What stadiums are hosting the 2026 World Cup in North America? See all 16
BMO Field – Toronto
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What stadiums are hosting the 2026 World Cup in North America? See all 16
SoFi Stadium – Inglewood, California
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What stadiums are hosting the 2026 World Cup in North America? See all 16
BC Place – Vancouver, Canada
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Hard Rock Stadium – Miami Gardens, Florida
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Lumen Field – Seattle
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What stadiums are hosting the 2026 World Cup in North America? See all 16
NRG Stadium – Houston
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Levi’s Stadium – Santa Clara, California
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Lincoln Financial Field – Philadelphia
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What stadiums are hosting the 2026 World Cup in North America? See all 16
Gillette Stadium – Foxborough, Massachusetts
Among the requests made by the scientists are longer hydration breaks and a clear policy around heat-related match postponements.
In a separate report released on Thursday, May 14, international scientific collaboration World Weather Attribution issued a similar warning.
According to World Weather Attribution, approximately 25% of World Cup games this summer are likely to be played when conditions exceed 26°C (78°F) on the Wet Bulb Globe Temperature (WBGT) scale – an index that calculates how well the body can cool itself.
"When WBGT exceeds 26°C, player performance can suffer. Above 28°C (82°F), the risk of serious heat illness becomes more concerning – not only for players, but also for the hundreds of thousands of fans in stadiums and outdoor fan festivals," World Weather Attribution said.
According to global players' union FIFPRO, games in which the WBGT exceeds 28°C should be postponed.
Many of the World Cup's hottest host cities, such as Atlanta, Houston and Dallas, have indoor stadiums with air conditioning, but even at those venues fans gather outdoors for pre-match activities and at fan festivals.
Other potentially dangerous venues such as Miami, Kansas City, New Jersey and Philadelphia, are outdoors.
In a statement, FIFA said that it is "committed to protecting the health and safety of players, referees, fans, volunteers and staff."
The governing body added that it is taking a number of precautions including allowing fans to bring in water bottles for games with high temperatures, and providing cooling areas for fans at outdoor stadiums.
FIFA has also attempted to limit games scheduled in the hottest part of the day in cities with outdoor stadiums. That has led to a number of games kicking off after the sun has gone down.
This article originally appeared on USA TODAY: World Cup 2026: Scientists warn of heat risks for players, fans
