Why Climate Scientists Say the 2026 World Cup Heat Poses a Danger to Players and Fans

The Climate Science Behind the Warnings

Two major climate research groups have conducted the most detailed analyses to date.

World Weather Attribution (WWA), a network of 15 climate scientists, analyzed the historical climate record at each host venue against each match's scheduled kick-off time. Their finding: dangerous heat and humidity are nearly twice as likely now as they were when the United States hosted the 1994 World Cup. Around a quarter of matches (26 of 104) are expected to be played under conditions that exceed FIFPRO's safe-play limits . The group estimates that roughly five matches could reach WBGT levels above 28°C, the point at which FIFPRO advises postponement .

Climate Central examined temperature trends across all 16 host stadiums. Their research found that nearly every venue now experiences more extremely hot June–July days than it did in 1970, and that human-driven climate change accounts for roughly 49% of all extremely hot tournament-period days since then . In a match-level assessment published in June 2026, Climate Central reported that climate change is increasing the likelihood of performance-impairing heat at 97 of the 104 scheduled matches — nearly the entire tournament .

These findings are not marginal. They describe structural changes in the North American climate that make summer outdoor football materially more dangerous than it was a generation ago. For 26 matches, climate change is estimated to increase the likelihood of dangerous heat by at least 10 percentage points, and for some fixtures — such as the June 26 group-stage match between Uruguay and Spain — the boost is among the largest in the tournament .

The Hottest Cities on the World Cup Map

Not all host cities face the same level of heat risk, but the most dangerous venues share a critical vulnerability: open-air stadiums in hot, humid regions with summer afternoons that routinely push WBGT past 28°C. A study published in the Journal of Biometeorology found that 14 of 16 host locations exceed this threshold at some point during tournament windows, and four locations exceed it more than half the time in an average year, rising to nine in the hottest year on record .

Miami — Hard Rock Stadium

Miami is currently the highest-risk World Cup venue. The open-air Hard Rock Stadium is situated in a region where Climate Central has identified extreme June–July heat as more common than at any other host site. The area now experiences approximately two additional weeks of extreme heat compared to the 1970s . All matches scheduled at Hard Rock Stadium are expected to exceed critical temperature thresholds . WBGT levels commonly approach 31°C, which is well into the "unsafe for play" zone .

Houston — NRG Stadium

Houston competes with Miami for the title of most heat-exposed venue. The region regularly reaches WBGT maxima near 31°C, frequently exceeding safety thresholds for both players and support staff . Houston's NRG Stadium is one of two venues that Climate Central identified as leading the hemisphere in extreme heat risk, alongside Miami . Although the stadium has a retractable roof, the surrounding fan environment and the overall heat burden on matchdays remain severe.

Monterrey — Estadio BBVA

Monterrey represents the highest-risk location in Mexico. It is a hot, humid city where WBGT readings routinely approach 31°C, often exceeding safe-play thresholds during afternoon windows . The venue is open-air, meaning that without active cooling, the conditions inside the stadium closely track outdoor heat stress. Multiple studies have listed Monterrey alongside Houston and Miami as a top-tier heat-risk venue .

Arlington — AT&T Stadium

Arlington sits in the Dallas–Fort Worth corridor, which climate scientists have identified as a high-risk zone. The region faces some of the most extreme projected heat among all U.S. host cities . While the stadium itself is air-conditioned, the broader metroplex heat exposure is among the worst in the tournament. The Dallas area was flagged by the Pitches in Peril report as one of the most climate-vulnerable World Cup sites, with projections of 100–160 days of unplayable heat by mid-century .

Atlanta — Mercedes-Benz Stadium

Atlanta hosts one of the tournament's semifinals. While Mercedes-Benz Stadium's retractable roof provides some mitigation, the southeastern U.S. climate means hot, humid conditions will dominate the fan experience outside the stadium, and the indoor environment still requires substantial cooling to stay within safe limits. Atlanta was identified in multiple analyses as a high-heat-stress venue in the absence of active climate control .

How Heat Threatens a Footballer's Body

To understand why these WBGT numbers matter, it helps to understand what happens inside the body of an elite footballer playing in these conditions. Dr. Madeleine Orr, an assistant professor of sport ecology at the University of Toronto, explains that the risk is not just discomfort but a cascade of physiological failures:

"Extreme temperatures can be particularly harmful as the body produces heat while exercising and needs to release that heat in order to cool down. But if the ambient temperature and humidity are too high and it's impossible to sweat effectively, that can lead to trouble pretty quickly, starting with symptoms like fatigue, cramping, and nausea, progressing to more serious conditions like heat exhaustion, heat stroke, and even death."

WBGT measures exactly this danger. Unlike simple air temperature, it combines heat, humidity, sunlight, and wind to estimate how much heat stress the human body actually experiences . When the WBGT passes 26°C, the body's ability to shed heat through sweating begins to degrade. At 28°C and above, most expert guidelines — including those from FIFPRO — consider conditions unsafe for professional football, regardless of fitness level .

The Gap Between FIFA and FIFPRO

The divide between what FIFA requires and what the global players' union FIFPRO recommends is one of the central tensions of this World Cup.

FIFPRO guidelines:

• At WBGT ≥ 26°C, cooling breaks should be implemented in both halves, typically around the 30th and 75th minutes .
• At WBGT ≥ 28°C, conditions are considered unsafe for play and postponement is advised .
• At WBGT ≥ 32°C, training and matches should be cancelled .

FIFA's actual rulebook:

• Cooling breaks become mandatory when WBGT exceeds 32°C, not 26°C .
• Before a match, if WBGT is near or above 32°C, organizers must discuss what precautions to take, but the decision to postpone is at the organizer's discretion — and FIFA has no mandatory postponement threshold .
• At this World Cup, a special provision allows cooling breaks regardless of temperature, which slightly narrows the gap but leaves the underlying thresholds unchanged .

The consequence is that many matches projected to fall between 28°C and 32°C WBGT will go ahead under FIFA's rules even though FIFPRO — and a growing chorus of independent scientists — say they should be postponed. The open letter to FIFA from more than 20 international experts in health, climate, and athletic performance calls this discrepancy "impossible to justify" based on current evidence .

FIFPRO has also begun exploring structural changes, including lengthening halftime to 20 minutes and introducing more frequent cooling breaks in both regulation and extra time . No such changes have been adopted for 2026.

What FIFA Has Put in Place — and What It Has Not

FIFA has taken several steps to address heat at this tournament, and it deserves credit for some meaningful operational shifts:

• Scheduled cooling breaks: now available regardless of WBGT, and mandatory once WBGT reaches 32°C, at approximately the 30th and 75th minutes .
• Adjusted kick-off times: matches in hotter cities have been shifted toward later afternoon and evening windows to avoid the most intense solar radiation, though many games still fall in high-heat periods.
• Player hydration: water bottles are explicitly permitted on the field during stoppages.
• Shaded benches and cooled dugouts: teams have access to shaded recovery areas with cooling equipment on the sideline.
• Enhanced medical readiness: additional medical staff and heat-illness protocols have been deployed at each venue.

Still, these measures do not address the core problem: matches are being played in conditions that a substantial body of scientific evidence says are unsafe. The Pitches in Peril report, compiled by Football for the Future, Common Goal, and Jupiter Intelligence, concluded that 14 of 16 venues already exceed safe-play thresholds for extreme heat, unplayable rainfall, and flooding . By 2050, the report projects that nearly 90% of World Cup stadiums will face unsafe extreme heat conditions, and 11 stadiums will experience unplayable heat. Four cities — Miami, Houston, Dallas, and Monterrey — stand at risk of 100 to 160 days per year of unplayable heat within two decades .

This is why some observers have described 2026 as "North America's last chance to host the tournament without immediate climate adjustments" . Many climate scientists now expect that future men's World Cups will need to shift permanently to cooler months, making this potentially the last summer World Cup as the sport has always known it .

What Happens Next

The most immediate variable left on the table is match-day decision-making. Under FIFA's current framework, the decision to delay or postpone a match because of heat falls to competition organizers, not to an independent medical authority or a fixed WBGT threshold. That means a high-profile knockout game in Miami or Houston could proceed at 31°C WBGT — above FIFPRO's "unsafe" level — if organizers choose not to intervene.

A second variable is fan exposure. While much of the analysis has focused on players, millions of supporters will travel to host cities during some of the hottest weeks of the North American year. Stadium surroundings, fan zones, and public transit will all be affected by the same heat, and few host cities have detailed public-facing plans for large-scale heat relief outside the venues themselves. The NPR analysis noted that 67 of 104 matches are set for times and locations that pose potential danger for heat-related illness, with 39 categorized as high risk .

What is certain is that the 2026 World Cup will be a real-world stress test for the relationship between global sport and a warming planet. It will take place across a continent where the frequency of extremely hot summer days has tripled since the last time it hosted, where fossil-fuel pollution drives roughly half of that excess heat, and where 14 of 16 host cities — from Miami to Monterrey — already surpass a scientifically grounded safety threshold . The question that climate scientists are now asking is not whether the heat will be dangerous, but whether the sport's governing body is willing to act like it.