England and Norway are heading into a World Cup quarter-final in Miami with a forecast that reads less like a sports note than an occupational safety problem. Scientists cited by WIRED say Saturday’s match is expected to combine South Florida heat, heavy humidity and direct sun, with a plume of Saharan dust moving across the Atlantic and through Florida adding to the hostile air.
For Norway’s men, the match is already a first: the Scandinavian team is preparing for the biggest game in its history. The environmental part is also outside the normal operating range for players from northern Europe. England’s players are hardly locals either, and both teams face conditions far removed from the Premier League and Eliteserien rhythms their supporters usually watch.
The useful number here is wet-bulb globe temperature, or WBGT. Unlike a normal air-temperature reading, WBGT accounts for humidity, wind and solar radiation. Humidity matters because sweat cools the body only when it evaporates. Wind can help move heat away. Sunlight heats skin and can raise core temperature. It is the least glamorous metric in the stadium, and probably the one FIFA should be staring at.
Saturday’s Miami forecast puts the match at about 88 degrees Fahrenheit, or 31 degrees Celsius, on the WBGT scale, according to WIRED. The American College of Sports Medicine recommends stopping athletic activity once WBGT rises above 82 degrees Fahrenheit, because the body struggles to shed heat and core temperature can climb quickly.
FIFA’s own emergency care manual sets a higher trigger. If WBGT exceeds 90 degrees Fahrenheit, FIFA says players and referees should get cooling breaks after 30 and 75 minutes, using towels soaked in ice water. That policy may still leave a match played in conditions that sports-medicine researchers regard as unsafe for sustained exertion.
Matt Maley, an environmental ergonomics and physiology researcher at Loughborough University in the UK, told WIRED that the heat could change the game itself. He said players may cut back on sprinting or cover less ground. That is the body doing resource management, no tactics board required.
Maley also warned that elite competition can override the internal warnings that usually make people slow down. Players trying to run the same distances and hit the same sprint numbers in extreme heat can put themselves at risk of heat exhaustion, he told WIRED.
The concern is not limited to the pitch. Scientists from the New Weather Institute warned in a report that fans in high-heat stadium conditions can face dehydration, heat exhaustion and heat stroke, with older supporters and people with existing health conditions at greater risk.
A separate coalition of scientists from five continents wrote to FIFA and World Cup participants in May, saying FIFA’s current heat-stress rules are not enough to protect players at the 2026 men’s World Cup. The group said three-minute hydration breaks are too short for meaningful cooling and rehydration. It recommended doubling those breaks and postponing matches forecast to reach a WBGT of 82 degrees Fahrenheit.
Miami has been getting hotter in recent years, with heat trapped by concrete and by greenhouse gases released from burning fossil fuels, according to climate data cited by WIRED. That turns a quarter-final into a test of tournament planning as much as endurance. The ball will still roll, unless officials decide otherwise. The human cooling system has less room for improvisation.
This story draws on original reporting from WIRED.
