The 2026 FIFA World Cup heads into Sunday’s final after experts documented dangerous heat at more than one in four matches, making it the hottest edition of football’s biggest tournament on record.
Defending champions Argentina, led by Lionel Messi, will take on a resurgent Spain side spearheaded by teenage sensation Lamine Yamal at MetLife Stadium in East Rutherford, New Jersey on Sunday, 19 July. But as football’s showpiece event reaches its climax, scientists say the tournament has also become a stark illustration of how climate change is reshaping the world’s most popular sport.
The warning has taken on added urgency ahead of the final, with wildfire smoke drifting south from Canada expected to combine with high temperatures to create unhealthy air quality conditions across parts of New York.
New York officials have warned that smoke from wildfires in Canada, coupled with elevated temperatures, could create unhealthy air quality conditions around the time of Sunday’s final.
New York State Governor Kathy Hochul said authorities were closely monitoring the smoke plume as it moved across the state.
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Sport is the world’s greatest unifying force, and football is the world’s biggest sport. If people who love football speak up to protect it from climate impacts like extreme heat, it will be a game-changer.
Simon Stiell, executive secretary, UN Climate Change
“Distant wildfires have impacted New York State in recent years, and this week unfortunately will be no different with expected hazy skies and poor air quality,” Hochul said. “We are now closely tracking these conditions. Sensitive groups should take particular caution.”
The state issued an Air Quality Health Advisory for fine particulate matter (PM2.5), warning that smoke from Canadian wildfires could cause temporary spikes in pollution. Forecasts indicated the Air Quality Index could exceed 150 in some areas, a level considered unhealthy for everyone.
Health officials urged residents and visitors, particularly children, older adults and people with heart or lung disease, to limit strenuous outdoor activity if air quality deteriorates.
The final is scheduled to kick off at 3 p.m. local time at MetLife Stadium, an open-air venue in the New York metropolitan area that has already experienced periods of high humid heat during the tournament.
Simon Stiell, executive secretary of UN Climate Change, said this year’s tournament had returned to many of the same North American host cities as previous World Cups, but under dramatically different climate conditions.
“This World Cup returned to many of the same cities as 1986 and 1994, but it did not return to the same climate. Extreme heat is much more frequent, and wildfires and storms more severe, because humanity is still burning colossal amounts of coal, oil and gas, which is baking our planet,” Stiell said.
Pyrotechnics mark the start of Paraguay’s World Cup match against the United States at SoFi Stadium in Los Angeles, California, in June. Image: US Department of State, CC BY-SA 3.0, via Flickr.
He said the impacts extended beyond football, affecting “the things we all need — like a stable climate, clean air and affordable food — as well as the things we love, like football and other sports.”
“On the pitch, at every level — from the highest levels of international football to the grassroots game — it means more extreme heat. More fatigue. Harder decisions, slower reactions, players and fans in the red zone,” he underscored.
Tournament lived up to pre-event heat warnings
The conditions surrounding the final follow weeks of matches played in oppressive heat across North America, validating scientific warnings issued before the tournament began.
A Reuters analysis of the first 94 matches found that 35 were played above the 26°C Wet Bulb Globe Temperature (WBGT) threshold at which the global football players’ union FIFPRO recommends enhanced cooling measures, while 27 exceeded the 28°C threshold where match delays or rescheduling should be considered. Even after excluding climate-controlled venues, nine matches in open-air stadiums surpassed that higher benchmark.
Heat risk is commonly assessed using Wet Bulb Globe Temperature (WBGT), which combines air temperature, humidity, sunlight and wind into a single measure of heat stress on the human body. While FIFA mandates cooling breaks only at higher WBGT levels, FIFPRO recommends protective measures and potential scheduling changes at lower thresholds.
The Reuters findings broadly align with research by World Weather Attribution, which projected that 26 of the tournament’s 104 matches would be played under hazardous heat conditions and found that climate change increased the likelihood of dangerous humid heat during 25 group-stage fixtures.
Some of the tournament’s most severe heat was recorded in Miami, where Uruguay’s group-stage matches against Cape Verde and Saudi Arabia were estimated to have reached around 33°C WBGT. England’s quarter-final victory over Norway was also played in soaring temperatures at Hard Rock Stadium, one of the tournament’s highest-risk venues for heat exposure.
MetLife Stadium, which will host the tournament final, is projected to experience 38 days each year above 32°C WBGT and 11 days above 35°C by 2050 due to climate change. Image: Keith H Putna, CC BY-SA 3.0, via Flickr.
The conditions matched pre-tournament warnings. Research published in the International Journal of Biometeorology projected that 14 of the tournament’s 16 host stadiums would exceed the critical 28°C WBGT threshold during this year’s competition, prompting researchers to recommend scheduling matches outside the hottest parts of the day and expanding heat management measures.
Scientists say such conditions can affect not only player safety but also performance, forcing athletes to conserve energy and make tactical decisions about when to press, sprint or recover during matches. Similar concerns are emerging across elite sport.
A 2023 World Athletics survey of nearly 400 athletes found that 75 per cent said climate change was negatively affecting their health and performance, while 85 per cent believed global heating had already had adverse consequences for their sport.
The mounting evidence has fuelled growing concern not only about the safety and performance of elite footballers, but also about the health of stadium workers, volunteers and the millions of supporters expected to attend future tournaments as extreme heat becomes more frequent.
“Sport is the world’s greatest unifying force, and football is the world’s biggest sport. If people who love football speak up to protect it from climate impacts like extreme heat, it will be a game-changer,” concluded UN’s Stiell. “Because this isn’t just about saving sport. It’s about protecting the world sport depends on — that we all depend on.”
