As World Cup arrives, Miami’s heat and humidity a concern for players, fans

The World Cup is going to be hot, and no place is going to be hotter than Miami — literally.

For Monday’s first match in Miami Gardens, where Saudi Arabia takes on Uruguay, Weather Underground forecasts 87 F, about 31 C, with a feels-like 96 F, almost 36 C, and a 52% scattered thunderstorm chance.

The average temperature at 5 p.m. — the earliest kickoff time for any of the seven Miami matches— during the month of June in the Miami area was 84.5 F, or 29C, between 2006 and 2020, according to data from the National Oceanic and Atmospheric Administration. That is 1.1 degrees higher than averages between 1981 and 2010, at 83.4 F. And unlike other high-temperature cities like Atlanta or Dallas, the city’s Hard Rock Stadium lacks a key feature: air conditioning.

“It’s going to be one of the hottest World Cup host cities, and there’s no air conditioning,” Jenna Lamb, U.S. director of Where Football Lives, a campaign drawing attention to the threats heat and extreme weather events pose to the sport, told the Herald.

To help players and fans deal with the heat, all matches in Miami kick off at 5 p.m. or later, and each of the 90-minute halves will be interrupted by a break so athletes can rehydrate. “It’s kind of crazy that we now, at the highest level of football, with the highest level of fitness and medical attention and preparation, we have to stop for three minutes a half to give players water,” Lamb said.

The threat is serious and potentially deadly as the human body typically functions at about 98.6 F, or 37 C. If the body’s temperature begins to deviate, our internal organs begin to make adjustments to continue to function, Orlando Laitano, an assistant professor at the University of Florida’s department of applied physiology and kinesiology, said. “So you can say hearts, the skeletal muscles, the brain, the lungs, they will have to work harder,” he said.

Eventually, the ways in which our body tried to cope — by sweating, for example - no longer suffice, which can result in illnesses like heat stroke, which typically starts when core temperature hits 104 F or more and can lead to death. Each year, about 500,000 people across the globe die from heat-related illnesses, according to the World Health Organization.

Those exercising outdoors are affected even more, as their body temperatures increase from both the external heat and the increased metabolic rate that is heating the body from within.

The type of heat players will experience in Miami is expected to affect their performance, because the body self-regulates to “avoid reaching catastrophic temperatures,” said Laitano. “So both teams are going to decrease the pace of the game just because of the heat,” he said.

In 1994, when the U.S. last hosted a World Cup, players spoke about the struggle to perform in locations like Orlando, where temperatures rose to 95 F, or 35 C. During the 2024 Copa America, a referee collapsed from heat illness in Kansas City, and a player for Uruguay had to be substituted after experiencing heat-induced dizziness in Miami.

Laura Biondo, a champion at freestyle football who lives in Miami and holds 15 Guinness World records understands what a difference heat makes. “It makes it harder to perform, and harder to recover. The heat is something that really fatigues you,” Biondo said.

On Saturday, Biondo was one of 511 people who drew attention to the long-term threat climate change poses to the sport by simultaneously juggling a football for ten seconds in Miami Beach’s Lummus Park, setting a new Guinness World Record.

Though the event was fun, everybody could feel the heat, she said. “The next day I could totally feel it — spending so many hours in the heat, it takes a toll on the body for sure,” she told the Herald.

Not just the heat, but the humidity

For athletes playing in South Florida, it’s not just the heat, it’s also the humidity that will affect their performance. The higher the humidity, the more the human body struggles to deal with the heat because the air is so saturated with moisture that the sweat that would otherwise cool us down can’t evaporate, Laitano said.

“If there is no evaporation, there is no way you can lose the heat, and therefore you sweat, but you continue to heat up your body,” he said.

Because humidity is such a big factor in how we experience and cope with heat, medical experts and organizers of sporting events like the World Cup have to take into consideration the wet bulb globe temperature (WBGT), a metric that also takes humidity into account, providing a better understanding of how the human body is affected by outside conditions.

With an average humidity of 76 % in the month of June, Miami’s wet bulb globe temperature at 5 p.m. is around 78 F, about 26 C. At that level, even the US military limits “very heavy work” to 45 minutes.

At about 78.8 F, or 26 C, scientists would consider a sporting event too risky for heat-related illnesses, “like people collapsing, passing out, maybe in some extreme cases, they may develop heat stroke, which would be fatal,” Laitano said.

FIFA, the global governing body for football, however, said it would only consider postponing a match at 89.6 F, or 32 C, wet bulb globe temperature or more.

“It is a big difference, so the risk is there,” Laitano said of how far FIFA deviates from medical experts’ point of view. FIFA did not reply to the Herald’s request for comment.

As average temperatures rise due to human-produced greenhouse gases warming the climate, scientists project that by 2050, more than half of the days of an average year in Miami will be warmer than 90 F.

And while stadiums can be retrofitted with air conditioning, Lamb’s worry is for the grassroots.

“Football doesn’t just live in stadiums, it also lives on beaches and in parks and streets,” she said. “The professional game, the highest level, wouldn’t exist without this grassroots game, and the grassroots are disproportionately impacted by the increasing extreme weather,” she said. “You have to ask yourself, where does this stop?”