"Impossible to justify." That's how 21 climate scientists and physiologists described FIFA's current heat safety guidelines in a letter sent last month. With the 2026 World Cup kicking off Thursday across North America, it's a phrase that's going to hang over this entire tournament.
According to World Weather Attribution — a climate science initiative at Imperial College London — a quarter of all 104 matches are expected to be played at or above a wet bulb globe temperature of 26 degrees, the point at which heat strain becomes a genuine risk for players. Five games are likely to exceed 28 degrees, the threshold deemed "unsafe" by both the players' union and the American College of Sports Medicine.
FIFA's own guidelines don't flag potential postponement until 32 degrees. That four-degree gap is not a technicality. That's the difference between a game being uncomfortable and a game being dangerous.
What the heat actually does to a match
Professor Mike Tipton of the University of Portsmouth's Extreme Environments Laboratory put it plainly: under hot conditions, sprinting frequency drops, players cover shorter distances, and games are more likely to end in a penalty shootout. The spectacle suffers. The sport gets slower, more cautious, more attritional — and the risk of heat exhaustion or heat stroke rises throughout.
England have been training in the Miami sun specifically to acclimatize. Miami, along with Kansas City and Philadelphia, is one of the venues most likely to hit that 28-degree danger threshold. There's no climate-controlled stadium there to absorb the problem.
The tournament is also 40 matches longer than any previous World Cup — 104 games in total. More matches in more cities across a North American summer means more exposure, not less. The venues in Atlanta, Dallas, and Houston offer climate-controlled stadiums, but even there, fans queueing outside or gathering in public viewing areas face the same unmanaged heat.
What FIFA is actually doing
The measures in place are not nothing. This is the first World Cup to mandate three-minute cooling breaks midway through each half. Climate-controlled substitutes' benches will be installed at outdoor venues. Several games have been moved to evening kick-offs. FIFA says venues will deploy misting systems, shaded areas, cooling buses, and expanded water distribution when forecasts are severe.
But critics argue the baseline threshold for action is still set too high, and the scientists' letter suggests the governing body has been slow to absorb what the research is actually showing.
The 1994 World Cup — the last time North America hosted — was played in a world roughly 1.3 degrees Fahrenheit cooler than today. Extreme heat events in June and July have on average tripled across the 10 host cities that were used back then. That's not a backdrop detail. That's the context in which every match will be played.
At the French Open last month — Paris's hottest May on record — Czech player Jakub Mensik was taken off court in a wheelchair after collapsing. He called the heat "insane." Football involves 90 minutes of continuous high-intensity running. The comparison is uncomfortable but relevant.
For anyone with a stake in how teams perform across this tournament, conditions will matter. High-heat matches statistically produce lower-intensity football and more draws — which reshapes how group-stage dynamics play out and which squads, with greater depth and fitness reserves, are best positioned to grind through a bloated 104-game bracket in a North American summer.
"Climate change is now affecting the spectacle that you see," Tipton said. He's right. And the question now is whether the spectacle will hold up for six weeks of it.
