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

The analysis found that roughly 20 of the tournament's 104 matches took place with Wet Bulb Globe Temperature (WBGT) at or above 28°C (82°F). WBGT is a composite measure that factors in temperature, humidity, wind speed, and solar radiation to gauge how much thermal stress the body is actually under — it is a more useful metric than air temperature alone because it accounts for how well the body can cool itself through sweating. At 28°C WBGT, that cooling mechanism becomes significantly compromised during sustained physical exertion. FIFPRO has identified 28°C as the point at which matches should be delayed or postponed to protect footballers' health. At the time of the analysis, 102 matches had been played and two remained, including the final, which was expected to proceed with a WBGT estimate just under 26°C (79°F), with low humidity easing the effects of high air temperatures (The Guardian).

A further 23 matches were played in cities experiencing dangerous heat and humidity, but in stadiums where air conditioning mitigated on-pitch conditions. The Guardian's findings build on earlier reporting throughout the tournament: a June 19 analysis identified two matches in Miami and Monterrey played in "severe heat" at levels FIFPRO had warned about; a June 30 report found that nine group-stage games were played 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 scope of the heat problem extends well beyond 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 degrade air quality in the region around the time of the World Cup final.

The Threshold Dispute

The gap between FIFPRO's recommended threshold and FIFA's operational guidelines is central to the disagreement. FIFA's own heat guidelines state that cooling breaks should be introduced and match delays or suspensions considered only when WBGT readings exceed 32°C (90°F) — four degrees above FIFPRO's recommended intervention point of 28°C. FIFPRO's heat guidelines also specify that an ambient temperature above 36°C (approximately 97°F) should trigger delays or postponements as an alternative to the WBGT threshold (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 in use during matches (The Athletic. FIFA had previously told the Guardian that it stations meteorologists 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 insufficient. In May 2026, scientists described FIFA's current heat safety measures for the men's World Cup as "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.

A Long-Standing Concern

FIFPRO's concerns are not new. 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.

What This Means

The broader context here is the collision of a mega-sporting event's rigid schedule with climate-driven extremes that respect no calendar. The 2026 World Cup, spread across 16 cities in the United States, Canada, and Mexico during June and July, was always going to encounter summer heat. What the Guardian's cumulative reporting documents is the scale: roughly 43 of 104 matches, when accounting for both unmitigated severe conditions and those where air conditioning intervened, 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 intervention threshold — 26°C, 28°C, or 32°C — is not merely technical. Each degree represents a meaningful difference in physiological risk. FIFA's higher 32°C threshold allows more matches to proceed uninterrupted; FIFPRO's 28°C standard would have triggered interventions in roughly 19% of the tournament's fixtures.

The fact that FIFA and FIFPRO are now in post-tournament discussions suggests the 2026 experience may produce concrete protocol changes. Whether those discussions yield a formal adoption of FIFPRO's threshold, a compromise figure, or incremental adjustments to the existing hydration-break framework is an open question. What is clear is that the 2026 tournament has generated a substantial evidence base for reform, one that future host nations and tournament organizers will have to contend with.