Experts have warned that players and fans will face hazardous heat and humidity during the World Cup, with climate change significantly increasing temperature risks compared to the last US-hosted tournament in 1994, according to World Weather Attribution (WWA). Global players' union FIFPRO is also calling for protective measures ahead of this summer's tournament in the US, Mexico, and Canada.
Heat and Humidity Risks
The meteorological and climate network reported that about 25% of all 104 games are likely to be played when conditions exceed 26°C (78.8°F) on the wet bulb global temperature (WBGT) system, which measures how heat impacts the body's ability to cool itself. When temperatures exceed that benchmark, FIFPRO advises implementing safety measures such as cooling. Games at risk include the tournament final in New York and New Jersey on 19 July, as well as two quarter-finals and the third-place play-off.
Unsafe Conditions
WWA added that around five games are expected to occur when the WBGT is above 28°C (82.4F), a level FIFPRO considers unsafe for play and advises postponement. A WBGT above 28°C is equivalent to about 38°C (100.4F) in dry heat or 30°C (86F) in high humidity. Dr Vincent Gouttebarge, FIFPRO medical director, stated that these calculations are in line with FIFPRO's 2023 findings and justify the need for mitigation strategies to protect players' health and performance.
Climate Change Impact
Dr Friederike Otto, professor of climate science at Imperial College London and part of WWA, emphasised that climate change is having a real and measurable impact on holding World Cups during the northern hemisphere summer. She noted that half of human-induced climate change has occurred since the 1994 World Cup, and the final facing a risk of 'cancellation-level' heat should be a wake-up call for FIFA and fans.
Previous Complaints
The warnings follow last year's Club World Cup, where players and managers complained about extreme heat. Chelsea midfielder Enzo Fernandez reported feeling 'really dizzy' in 'very dangerous' heat, while England manager Thomas Tuchel said he may keep substitutes in the dressing room due to high temperatures.
Scientists' Demands
A letter signed by 20 world-leading scientists from the UK, USA, Canada, Australia, and Europe calls on FIFA to urgently overhaul its approach, including delaying or postponing matches above 28C WBGT, longer cooling breaks of at least six minutes, improved cooling facilities, and regular guideline updates based on the latest science.
FIFA's Response
FIFA declined to comment directly but stated it would use a 'tiered heat mitigation model' with measures adapted to real-time conditions. A spokesperson said dedicated meteorological support would monitor WBGT and heat index, and scheduling had been designed with climate in mind, including adjusted kick-off times, limited matches during hottest periods, and warmer fixtures prioritised for covered stadiums. FIFA added it would continue to monitor conditions and apply contingency measures.
England's Challenges
England's World Cup stars will face intense humidity and 'corn sweat' at their Kansas City base, where average highs reach 30-32°C (87F–90F). Corn sweat refers to humidity from corn plants releasing water vapour, making heat waves feel significantly hotter. England chose the location to reduce travel time and prepare for a potential trip to Mexico City in later rounds.
