The World Cup is here, and so is a major safety concern: heat. Multiple cities hosting matches typically see highs reaching the 90s for this time of year, including Houston, Miami, Monterrey, Arlington and Atlanta, but only some of them have a roof and air conditioning, so heat could be a major threat to players and spectators alike. Climate change has also increased the likelihood of problems due to the heat, but policies are in place in case things get too hot.