Climate change is increasing the likelihood that players will face heat conditions linked to reduced performance at nearly every match in the 2026 World Cup, according to new analyses by Climate Central and the World Weather Attribution group.
The Climate Central analysis found that 97 of the 104 scheduled matches will probably exceed 28°C, a temperature linked in sports science research to declines in player running intensity, speed and overall performance.
On Thursday, Bafana Bafana kick off their first World Cup in 16 years against co-hosts Mexico at the iconic Estadio Azteca in Mexico City. During the next six weeks, soccer fans will watch 48 teams from across the world compete for the coveted prize. Teams will compete in 104 matches across 16 cities in the US, Mexico and Canada.
Climate Central researchers say a sustained heat of 28°C or more can reduce the frequency and intensity of sprints, alter tactical approaches and place teams that rely on high-pressing systems at a disadvantage.
A World Weather Attribution assessment adds further detail on how conditions will vary across the 16 host cities in the US, Mexico and Canada. As the tournament spans a wide geographic range, the weather is expected to differ sharply between venues.
Coastal and northern cities, particularly in Canada and along parts of the US Pacific coast, are expected to experience relatively moderate temperatures.
In contrast, inland and southern locations in the US and Mexico are more likely to experience sustained heat, with daytime temperatures frequently approaching or exceeding 30°C during the tournament period.
The study emphasises that heat risk during football matches is driven not only by air temperature but also by humidity, which together determine wet bulb globe temperature (WBGT), a composite measure of heat stress that accounts for temperature, humidity, wind speed and radiant heat from sunlight.
WBGT is widely used in sports science and occupational health because it better reflects the physiological strain placed on the human body during physical activity than temperature alone.
Under guidance from international players’ union Fifpro, cooling breaks are recommended when WBGT reaches 26°C, while conditions at or above 28°C are considered unsafe for play and could require postponement.
Fifa’s regulations, however, mandate consideration of postponement at higher thresholds, underscoring a gap between athlete-centred guidance and governing-body rules, it notes.
The World Weather Attribution analysis found that several World Cup matches would probably be played under conditions that exceed the risk thresholds. It estimates that about 26 matches could take place at or above 26°C WBGT, with a smaller number reaching or exceeding 28°C WBGT.
While the most extreme conditions remain relatively rare, the study notes that the likelihood of hazardous heat has increased compared with previous decades.
One example highlighted is a late-afternoon match in Kansas City between the Netherlands and Tunisia, which carries a measurable risk of exceeding the 28°C WBGT threshold despite its evening kick-off time. This, it says, illustrates that scheduling alone could not fully eliminate heat exposure in hotter host cities.
Both Climate Central and World Weather Attribution compare present-day conditions with historical or counter-factual climates to isolate the role of human-caused climate change.
Their findings indicate that global warming has increased the likelihood and intensity of extreme heat during the World Cup period, compared with conditions during earlier decades, such as the 1994 tournament in the US.
The attribution analysis estimates that many host venues are experiencing WBGT levels about 0.5°C to 0.8°C higher than they would in a world without human-caused climate change.
It also finds that further warming of about 2°C above pre-industrial levels would substantially increase the frequency of dangerous heat conditions across multiple host cities.
Extremely hot conditions are expected to be most severe in inland US cities such as Dallas, Houston, Kansas City and Philadelphia, where the combination of high temperatures and humidity produces elevated heat stress.
By contrast, cities on the Pacific coast and in Canada are generally expected to experience lower risk, although occasional heat events remain possible across all venues.
The World Weather Attribution study also highlights a broader public health dimension. While air-conditioned stadiums in cities such as Atlanta, Dallas and Houston might reduce heat exposure inside venues, millions of fans attending outdoor events, fan zones and public screenings will remain exposed to high temperatures and humidity.
Researchers warn that this makes heat not only a performance issue for elite athletes but also a wider safety concern for spectators, stadium staff and support teams.
Climate Central’s analysis found that extremely hot days in June and July are on the rise at all but two of the 2026 World Cup stadiums. “Extreme heat can affect more than performance — it can pose a serious health risk, especially when combined with high humidity.
“To keep players, fans and staff safe, World Cup organisers are adapting to the rising heat risks with more evening matches in hotter cities and mandatory hydration breaks at all 104 matches. Matches might be postponed if the WBGT hits 32°C to minimise risks of heat stress.”
But most stadiums are open-air, “leaving players and millions of fans exposed to peak summer heat. Only three stadiums are fully climate-controlled (Atlanta, Dallas and Houston)”.