Nearly one in five matches at the 2026 FIFA World Cup were played in heat and humidity that the players' union says should have caused delays or postponements, according to a Guardian analysis published July 16, 2026.

The analysis found that about 20 of the tournament's 104 matches took place when a heat measure called Wet Bulb Globe Temperature, or WBGT, reached 28°C (82°F) or higher. WBGT is different from a regular weather forecast. It combines temperature, humidity, wind, and sunlight into one number that tells you how hard it is for the human body to cool itself down. When you exercise hard in high WBGT conditions, your body struggles to sweat enough to stay at a safe temperature. The players' union, FIFPRO, says 28°C is the point where matches should be paused or moved to a cooler time to protect players' health. At the time of the analysis, 102 matches had been played and two remained, including the final, which was expected to go ahead with a WBGT estimate just under 26°C (79°F), with low humidity making the high temperatures more manageable (The Guardian).

Another 23 matches were played in cities with dangerous heat and humidity, but inside stadiums where air conditioning cooled things down on the field. The Guardian's findings build on earlier reporting throughout the tournament: a June 19 analysis found two matches in Miami and Monterrey played in "severe heat" at levels FIFPRO had warned about; a June 30 report found nine group-stage games in severe conditions; and a July 3 report noted that a US heatwave affecting 250th anniversary events had also threatened World Cup fixtures, with France's match among those played at WBGT levels the union said should trigger delays (The Guardian).

The heat problem reached far beyond the stadiums. At the time of the Guardian's analysis, over 125 million Americans from California to New England were under dangerous heat alerts during a record-breaking heat wave. New York City Mayor Zohran Mamdani separately warned of health impacts from wildfire smoke expected to worsen air quality in the region around the time of the World Cup final.

Why FIFA and the Players' Union Disagree

The main disagreement is about where to draw the line. FIFA's own heat guidelines say that cooling breaks should be introduced and match delays or suspensions considered only when WBGT readings exceed 32°C (90°F). That is four degrees higher than FIFPRO's recommended intervention point of 28°C. FIFPRO's heat guidelines also say that if the regular air temperature goes above 36°C (about 97°F), matches should be delayed or postponed, even without looking at the WBGT number (FIFPRO). The 28°C WBGT threshold had not been officially accepted or adopted by FIFA as of mid-July 2026 (ESPN).

At the 2026 World Cup, three-minute hydration breaks were already being used during matches (The Athletic. FIFA had previously told the Guardian that it stations weather experts at matches. FIFA did not respond to the Guardian's request for comment on the July 16 analysis.

Scientists had warned before and during the tournament that FIFA's heat safety measures were not enough. In May 2026, scientists called FIFA's current heat safety measures for the men's World Cup "inadequate" and warned they could put players at risk of serious harm (BBC Sport. A group of experts, including UConn's Casa, urged FIFA to lower the WBGT threshold for match interventions to 26°C (78.8°F), two degrees below even FIFPRO's recommendation (UConn Today. A Mother Jones report noted that players in 2026 faced an even greater risk of unsafe temperatures than during the 1994 World Cup, the last edition held in the United States (Mother Jones.

These Concerns Are Not New

FIFPRO has been raising these issues for a while. In August 2025, FIFPRO, the Portuguese players' union SJPF, and the Portuguese Football Federation conducted a scientific study on how extreme heat affects players, during which FIFPRO stated that a number of games at the Club World Cup should have been delayed under its 28°C WBGT guideline (FIFPRO). The union's broader extreme-weather guidance also recommends cancelling and rescheduling training and matches when air temperature falls below -15°C (FIFPRO).

The institutional response appears to be gaining momentum. FIFA and FIFPRO were in discussions about heat protocols following the 2026 World Cup, according to ESPN reporting on July 12, 2026 (ESPN).

Joshua L DeVincenzo, assistant director at Columbia University's National Center for Disaster Preparedness, described the 2026 World Cup as a "stress test of heat mitigation and preparedness." Simon Stiell, executive secretary of the UN climate body (UNFCCC), provided an emailed comment for the Guardian article stating the climate crisis is affecting football and other sports.

The Bigger Picture

The broader context here is the collision of a massive sporting event's fixed schedule with climate-driven weather extremes that do not care about calendars. The 2026 World Cup, spread across 16 cities in the United States, Canada, and Mexico during June and July, was always going to face summer heat. What the Guardian's cumulative reporting shows is the scale: roughly 43 of 104 matches, counting both those played in severe conditions without relief and those where air conditioning helped, took place under heat and humidity levels that at least one major stakeholder considers dangerous to player health.

The dispute over where to set the WBGT threshold is not just a technical argument. Each degree represents a real difference in how much risk players face. FIFA's higher 32°C threshold allows more matches to proceed without interruption. FIFPRO's 28°C standard would have triggered interventions in roughly 19% of the tournament's matches.

The fact that FIFA and FIFPRO are now in post-tournament discussions suggests the 2026 experience may lead to concrete changes. Whether those discussions result in FIFA formally adopting FIFPRO's threshold, settling on a compromise number, or making smaller adjustments to the existing hydration-break system is an open question. What is clear is that the 2026 tournament has produced a substantial body of evidence for reform, one that future host nations and tournament organizers will have to deal with.