World Cup Faces Extreme Heat Risks as Players' Union Threshold Breached

The World Cup was always going to be hot. It has already become hazardous.

An analysis of the first round of group matches shows that two games were played in outdoor conditions so extreme they crossed a heat threshold that the global players’ union, Fifpro, has previously said should trigger a delay or postponement. Four more fixtures took place in cities where the heat was just as fierce, only softened by stadium air conditioning.

This is the tournament Fifa knew would be the hottest since the World Cup began in 1930. The opening week has started to show what that actually looks and feels like.

Miami and Monterrey at the edge

The most brutal conditions of the first 24 games came in Miami, where Saudi Arabia faced Uruguay. Sweden’s meeting with Tunisia in Monterrey ranked second among matches staged in stadiums without air conditioning.

Both were evening kick-offs. That barely helped.

Temperature and humidity data for those locations and kick-off times show wet-bulb readings of 28C (82F) or higher. That number matters. Fifpro has previously argued that games at or above a wet-bulb temperature of 28C should be delayed or postponed because of the risk to players. Asked about these findings, the union declined to comment on the specific heat situation at this World Cup.

The science behind that threshold is stark. Wet-bulb temperature combines air temperature, humidity and cloud cover to gauge how effectively the human body can cool itself through sweating. Once heat and humidity climb past a certain point, sweat stops evaporating properly. The body overheats quickly. The consequences can be severe: heat illness, organ failure, even death.

To assess conditions, the Guardian used weather data from government agencies in the US and UK and calculated wet-bulb values using a formula employed by authorities in countries including Australia and Canada.

Six games in the danger zone

The numbers from the opening round are sobering. Six of the first 24 matches were played in locations where wet-bulb temperatures reached 28C or higher:

• Germany v Curaçao in Houston
• Saudi Arabia v Uruguay in Miami
• Portugal v DR Congo in Houston
• Netherlands v Japan in Dallas
• England v Croatia in Dallas
• A second Houston fixture at that threshold

Houston and Dallas have air-conditioned stadiums, which pulled conditions on the pitch down to more tolerable levels. Outside, it was a different story.

On Wednesday in Dallas, England’s game against Croatia coincided with the fiercest wet-bulb reading so far, close to 35C (95F). Inside, the air conditioning dragged that down to around 22C (71F). For players, that intervention may have been the difference between an oppressive evening and something far more dangerous.

Yet the heat did not spare everyone. Record temperatures in several host cities left fans baking in open concourses and shadeless seating. Stadium workers, many of them on their feet for hours moving heavy equipment long before kick-off, faced potentially hazardous conditions.

Fifa’s response under scrutiny

Fifa anticipated a roasting North American summer and tried to act. Kick-off times have been nudged later in the day. Mandatory water breaks have been written into the matchday routine. A handful of the 16 venues have roofs or full stadium air conditioning, easing the worst of the heat for players and match officials.

Current Fifa guidelines say cooling breaks should be used when the temperature hits 32C (89F). In practice, referees at this World Cup have ordered drinks breaks at lower readings. Any decision to delay or suspend a match remains at the discretion of competition organisers.

On the eve of the tournament, a group of heat and public health experts warned that this might not be enough. In an open letter, they urged Fifa to adopt more extensive protections, explicitly citing Fifpro’s call for games to be delayed or called off when wet-bulb temperatures hit 28C.

Robbie Parks, an environmental epidemiologist at Columbia University and one of the signatories, underlined the gap between official readings and what people actually feel.

“Temperatures are often taken from shaded areas and if players are in direct sun, it can be double figures more than the temperature readings,” he said. “Standing in the sun can be dangerous even at lower temperatures, even above 23C (73F) or 25C (77F) would make me concerned for older adults out there for more than few minutes.”

Parks welcomed later kick-offs, air conditioning and water breaks as partial answers for players. His concern stretches further.

“Shade is super important and hydration is super important,” he said. “You need to allow people to bring in their own water and think about having misters for evaporative cooling. The final is going to be held in New Jersey, and that stadium isn’t covered which makes me worry. But I’d hope Fifa will learn the best way to deal with that by then.”

Climate crisis in the stands and on the pitch

The context looms over everything. Extreme heat is already the deadliest weather hazard intensified by the climate crisis, killing more people each year than hurricanes, floods and wildfires combined.

This World Cup will add to the problem. More than 100 matches spread across three countries means millions of extra journeys, vast energy use and heavy infrastructure demands. Greenly, a global carbon accounting platform, estimates the tournament will generate 7.8m tonnes of greenhouse gases – roughly double the emissions of the previous World Cup in Qatar.

The spectacle designed to unite the world around football is, at the same time, feeding the very crisis that makes playing and watching the sport more dangerous.

Fifa’s mitigation playbook

Fifa insists it is ready. A spokesperson said the governing body is “committed to protecting the health and safety of all players, referees, fans, volunteers and staff” at this World Cup.

Meteorologists have been stationed at match venues to track conditions and advise organisers. Tournament planning, Fifa says, involves “close coordination” with host cities, stadium operators and national agencies.

Ahead of kick-off, Fifa agreed a “tiered mitigation model” for extreme temperatures. As the heat index climbs, extra interventions are meant to kick in.

For players, that means:

• Mandatory hydration breaks
• Constant access to water and electrolyte drinks
• Cooling tools such as ice, cold towels, fans, mist and shaded areas

For spectators, elevated temperatures trigger:

• Additional shaded zones
• Misting systems
• Cooling buses
• Expanded water distribution

A new medical set-piece protocol for treating heat exertion has also been introduced, including the use of cooling bags for the first time.

Fifa says it will “continue to monitor conditions in real time, integrating wet bulb globe temperature and heat index surveillance, and stands ready to apply established contingency protocols should extreme weather events occur.”

The question now is not whether the heat will come. It already has. The real test is whether football’s rulers are willing to stop the show if the numbers – and the players’ bodies – say they must.