The 2026 tournament is being played across the United States, Canada and Mexico at 16 host cities, including locations accustomed to soaring summer temperatures and stifling humidity.
The weather has already had an impact, with France forced to sit through a two-hour storm delay in the group phase match against Iraq.
Now the National Weather Service is warning of rampaging temperatures in and around Kansas City, which is hosting matches and is also the training base for Argentina, England, the Netherlands and Algeria.
The Midwestern city's Arrowhead Stadium is the location for the last-32 match between Colombia and Ghana on Friday.
Monday's advisory from the National Weather Service warned of "dangerously hot conditions with heat index values up to 105 degrees Fahrenheit (41 degrees Celsius) to 110 Fahrenheit expected".
"Heat-related illnesses increase significantly during extreme heat and high humidity events," it added.
"Several days of extreme heat will impact the region with poor heat relief during the overnight hours."
The heat advisory runs until 21"00 on Friday (02:00 GMT Saturday).
World Cup 2026
The 2026 World Cup will be held from June 11th to July 19th in the United States, Canada and Mexico. The tournament will feature 48 national teams and will be played in 16 modern stadiums.
Match schedule and times | Draw | England at the World Cup | How Mexico's Azteca may affect England | How to watch the World Cup | Predictions and odds
Watch the World Cup 2026 live on ITVX via Prime Video here - live coverage, highlights, and analysis.
