FIFA, World Cup organisers, players and spectators.
As the knockout stage begins across North American host cities.
Extreme heat is expected to become a major issue in several World Cup host cities this week, with forecasts near 100F and heat index levels around 110F. Toronto, New York, Boston, Kansas City and Philadelphia are among the concern areas.
FIFA’s mandatory hydration breaks, previously criticised in milder conditions, could become important safeguards for players and fans. Indoor venues in Atlanta, Dallas and Houston are less exposed, while western host cities are expected to stay cooler.