There are six host cities (Miami, Houston, Dallas, Monterey, Kansas City and Atlanta) where WBGT can reach at least 32C (90F) during the afternoon, which is considered extreme heat stress where the body actually struggles to stay cool.
To reduce this risk, matches are usually scheduled outside the hottest hours of the day, with many kickoffs taking place in the late afternoon or evening. For example, the kick-off time for Scotland’s Group C match against Brazil in Miami is 18:00 ET (23:00 BST).
Some stadiums, including those in Houston and Dallas, have retractable roofs and climate control to ensure reasonable conditions.
Summer heatwaves are also common in North America and Mexico, where temperatures can rise more than 10C (18F) above average, potentially pushing things into much more difficult territory for players and fans alike.
For example, in New York, where this year’s World Cup final is held on 19 July at 15:00 ET (20:00 BST), a typical heat wave can cause extreme heat stress, with temperatures reaching the mid-30s C (mid 90s F) and WBGT around 30 C (86 F).
