FIFPro, the international players' union, says matches above 28°C wet bulb globe temperature should be postponed. FIFA's postponement threshold is 32°C, and five host cities already face the lower line almost every year of the tournament.
The 2026 FIFA World Cup opened four days ago in Mexico City, and within the first ten days of the tournament at least five of its 104 matches are projected to be played at a wet-bulb globe temperature of 28°C (82.4°F) or higher. That is the threshold at which FIFPro, the international players' union, says matches should be delayed or suspended. It is not the air temperature on a stadium thermometer. WBGT is a heat-stress index that combines air temperature, humidity, solar radiation, and wind speed, and it tracks how hot the body actually feels when it is working, not just how hot the air is.
The five matches almost certainly will not be the last ones played in dangerous heat. A match-by-match attribution analysis from the World Weather Attribution consortium projects that 26 of the tournament's 104 matches, roughly one in four, will be played at or above 26°C WBGT, the line at which FIFPro requires cooling breaks and additional medical supervision. Nine of those 26 are expected to be played in stadiums that do not have active cooling systems. Five matches in total are projected to cross the 28°C line, against three such matches recorded during the 1994 World Cup held in the same country. The probability of any single match exceeding the unsafe threshold is now nearly double what it was three decades ago, and the change is attributed to human-induced climate change, according to WWA's full attribution analysis.
The same five cities account for almost all of the high-risk matches. Miami, Kansas City, Philadelphia, Dallas, and Houston each show roughly a one-year return period for 82.4°F WBGT days during the June 11 to July 19 tournament window, meaning a heat-stress day at that level is more an annual expectation than a once-in-a-decade event. Atlanta, Boston, New York, and Monterrey enter the picture at the 26°C threshold. The cities where the chance of a 28°C-plus match has at least doubled since 1994 are a different list, and a more striking one: Los Angeles, Seattle, San Francisco, Monterrey, Toronto, and Vancouver, all of which were not on the original 1994 map and now face heat stress the older tournament never had to schedule around.
These projections are not climate speculation. They come out of WWA's standard rapid-attribution pipeline, the same group that now produces same-day analysis of heat waves and floods around the world, applied to a fixed tournament calendar. The model is also conservative. The WBGT numbers are derived from temperature and humidity alone, a method established by Zhang and colleagues in 2024, so they apply best to a sheltered, shaded, low-wind setting. Actual on-field WBGT can run higher in direct sun, and lower in a steady breeze, and the index does not capture metabolic heat from a player working at match intensity, or the insulating effect of a kit, according to Julien Périard of the University of Canberra's Institute for Sport and Exercise Research, who spoke to SMC Spain. The 28°C number is the floor, not the ceiling, of what players could face.
The match-level risk lines up with a stadium-level picture drawn in a 2024 peer-reviewed study. Lindner-Cendrowska and colleagues classified 10 of the 16 host stadiums as carrying "very high" extreme-heat risk, with Arlington's AT&T Stadium, Houston's NRG Stadium, and Monterrey's BBVA Stadium flagged as the worst for severe heat stress. Arlington and Monterrey are indoor or partially covered venues, which complicates the WBGT reading, but the broader conclusion holds: the tournament's hottest fixtures are concentrated in a small number of cities, and those cities' stadiums are exactly the ones that need cooling infrastructure the most.
What the data has not yet produced is a policy response that matches it. FIFA's 2026 player-welfare announcement mandates three-minute cooling breaks at the midpoint of each half, in every match, across the tournament. WWA's authors argue that hydration breaks alone are not enough, and recommend adjusted warm-up protocols, on-site medical staffing for both players and fans, and stadium-level cooling where it is feasible. The WWA analysis was not available when the 104-match schedule, the 16 host cities, or the kickoff times were set.
The unresolved decision is a numerical one. FIFPro's 28°C WBGT line for postponement is a players'-union standard, not a regulator's. FIFA's current match-postponement threshold is 32°C WBGT, four degrees higher. Whether a match at 28.5°C, 29°C, or 30°C gets played, paused, or moved will be decided on a case-by-case basis by match officials, medical staff, and the two competing federations on the day, with no public schedule of where that line actually sits in practice.
The climate context for the gap is a measurable one. Rubén del Campo, a spokesperson for AEMET, Spain's State Meteorological Agency, told SMC Spain that global average temperature has risen roughly 0.5 to 0.7°C since 1994, about half of all post-industrial warming, and that heat waves have intensified measurably since the mid-1990s. The 2026 World Cup is being played in the hottest summer the tournament calendar has ever run into, on a fixture list drawn up before its authors had the data to know that.
What to watch: kickoff times in Miami, Kansas City, and Houston in the first ten days of the tournament, and whether FIFA, the confederations, or the match officials invoke the cooling-break protocol or the postponement protocol in any of the projected 28°C-plus matches. The model is already published. The decision on whether to act on it is still being made in real time.