Hydration stations will be common around stadiums and organisers have repeatedly stressed the importance of staying hydrated. In many venues, free water refill stations will be available if you bring an empty clear plastic bottle.
Humidity will also be a major factor, especially in places such as Miami, Houston and parts of Mexico. Sun cream, hats and light clothing will quickly become essentials rather than luxuries.
Temperatures in some cities are expected to regularly exceed 30°C. Dallas organisers themselves admitted that some locals leave the city during summer because of the heat, which probably tells you everything you need to know.