Approximately 25 percent of the 104 matches scheduled for the 2026 FIFA World Cup could exceed recommended thermal safety limits, according to an analysis by World Weather Attribution. The tournament will take place from June 11 through July 19.

The probability of extreme heat conditions during the tournament is nearly double that recorded during the 1994 World Cup. This analysis concludes that at least five tournament matches will be played in conditions at or above 82 degrees Fahrenheit on the wet-bulb globe temperature index. Researchers used the index, which accounts for ambient temperature, humidity, solar radiation, and wind speed, to assess physiological heat stress risk.

Miami, Kansas City, Philadelphia, Dallas, and Houston have a one-year return period for conditions reaching 82.4 degrees Fahrenheit on the index during the tournament's scheduled dates. The probability of reaching this index has at least doubled since 1994 in Los Angeles, Seattle, San Francisco, Monterrey, Toronto, and Vancouver. The number of extreme humid heat events has more than doubled in most parts of the U.S. since 1980, and global climate change added approximately three weeks of dangerous humid heat in 2024.

A study published in Scientific Reports in late 2024 found 10 of 16 host stadiums present a high risk of extreme heat, specifically Arlington, Houston, and BBVA Stadium in Monterrey. Nearly half of scheduled matches have at least a 50 percent likelihood of conditions impairing athletic performance, particularly in southern U.S. areas and low-lying parts of Mexico.

FIFA announced three-minute hydration breaks at the halfway point of each half for all tournament matches. The match schedule was developed using a technical analysis of venues accounting for average temperatures, cooling infrastructure, public transport, and security conditions. Teams will use cold-water immersion tubs, ice vests, and misting fans to manage player temperatures. FIFPro established a wet-bulb globe temperature threshold of 26 degrees Celsius for additional measures, while 28 degrees Celsius is classified as high risk.

"This set of studies underscores the need to plan ahead for major events such as the World Cup, as well as implement proactive policies to mitigate heat. As the wet-bulb globe temperature index only considers environmental conditions and does not incorporate sport's own metabolic heat production or the insulating effects of clothing, which can limit heat loss, more advanced models and predictive tools are required to ensure the safety of athletes," Julien Périard said.

"It is a figure that may not seem very high, but it represents approximately half of the warming observed in the last century and a half. Moreover, since the mid-1990s, when the previous World Cup was held in the United States, the effects of climate change have intensified all over the planet, especially heat waves," Rubén del Campo said.