World Cup Begins Under Extreme Heat Conditions

The World Cup promised a festival of football across the US, Mexico and Canada. What it has delivered in its opening round of matches is a stark glimpse of the sport’s future in a heating world.

Two of the first 24 games were played in outdoor conditions so extreme they crossed a red line previously set by Fifpro, the global players’ union – a level at which it says matches should be delayed or postponed. Four more took place in cities beyond that same heat threshold, saved only by the thrum of stadium air conditioning.

The ball is rolling. So is the thermometer.

Miami and Monterrey at the limit

Saudi Arabia’s meeting with Uruguay in Miami topped the list. Of all the first-round fixtures analysed, it was played in the most severe heat where no roof or stadium cooling system could soften the blow.

Sweden v Tunisia in Monterrey came next among open-air venues. Both games were evening kick-offs. It barely helped.

According to temperature and humidity data for those locations and kick-off times, players were operating in wet-bulb temperatures of 28C (82F) or higher. That number is not a curiosity for weather obsessives. It is the line Fifpro has previously argued should trigger a delay or postponement.

Asked to respond to the findings, the union declined to comment on the specific conditions at this World Cup. The broader backdrop is chilling in a different way: forecasts suggest this will be the hottest World Cup since the tournament began in 1930.

When sweat stops working

Wet-bulb temperature is the measure that matters here. It blends air temperature, humidity and cloud cover to show how well the human body can cool itself through sweating. Beyond a certain point, sweat no longer evaporates properly. The body overheats. Illness and, in extreme cases, death can follow quickly.

The Guardian’s analysis used weather data from government agencies in the US and UK and calculated wet-bulb readings via a formula used by authorities in several countries, including Australia and Canada.

The results underline the scale of the problem. Six of the first 24 matches were staged where wet-bulb temperatures reached 28C or above:

• Germany v Curacao in Houston
• Saudi Arabia v Uruguay in Miami
• Portugal v DR Congo in Houston
• Netherlands v Japan in Dallas
• England v Croatia in Dallas
• and one further game in Houston

Houston and Dallas both benefit from air-conditioned stadiums. Miami and Monterrey do not.

Air conditioning buys time – but not for everyone

In some arenas, technology is holding the line. On Wednesday in Dallas, England’s match against Croatia took place in the fiercest wet-bulb conditions recorded so far, close to 35C (95F) outside. Inside, the stadium’s air conditioning dragged that down to around 22C (71F), a far more manageable environment for elite athletes.

But the comfort inside the bowl does not tell the whole story. Record-high temperatures in some host cities left fans wilting in shadeless concourses and walkways. Stadium workers, many of them on their feet for hours lugging equipment or staffing kiosks, faced far harsher exposure than the players they serve.

Current Fifa guidelines call for cooling breaks at 32C (89F) and above, though drinks pauses have been granted at lower readings during this tournament. The decision to delay or suspend matches remains at the discretion of competition organisers.

That discretion is now under sharper scrutiny.

Experts warn: 28C is not a luxury line

On the eve of the World Cup, a group of heat and public health specialists sent an open letter to Fifa, urging stronger protections and explicitly backing Fifpro’s call for games to be halted once conditions reach a wet-bulb temperature of 28C.

“Temperatures are often taken from shaded areas and if players are in direct sun, it can be double figures more than the temperature readings,” said Robbie Parks, an environmental epidemiologist at Columbia University and one of the signatories.

“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 acknowledged that air conditioning, later kick-off times and water breaks will help players. His concern stretches beyond the pitch.

“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.”

Football’s climate contradiction

Extreme heat is already the deadliest climate-related hazard on the planet, killing more people each year than hurricanes, floods and wildfires combined. This World Cup, a global celebration of sport, is also fuelling the very crisis that is making it harder to stage.

More than 100 matches, long-haul flights, vast temporary infrastructure: Greenly, a carbon accounting platform, estimates the tournament will generate 7.8m tonnes of greenhouse gases. That is roughly double the emissions of the previous World Cup in Qatar.

The sport is colliding with its environment in real time.

Fifa’s response: mitigation and monitoring

Fifa insists it is ready for the challenge. 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 advise on extreme weather, with planning built around “close coordination” with host cities, stadium authorities and national agencies. Ahead of the tournament, Fifa agreed a “tiered mitigation model” for extreme temperatures, with extra interventions triggered at different thresholds.

For players, that means mandatory hydration breaks, access to water and electrolyte drinks and a range of cooling tools: ice, cold towels, fans, mist and shaded areas on the sidelines.

Spectators are promised their own protections when temperatures climb. Stadiums can activate extra cooling capacity, shaded zones, misting systems, cooling buses and expanded water distribution.

A new medical protocol for treating heat exertion has also been rolled out, 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 whether monitoring and mitigation can keep pace with a tournament already brushing up against the limits of safe play – and what happens when the next World Cup pushes those limits even further.