Extreme heat and severe weather are posing significant risks across North America as the 2026 World Cup begins. According to NBC News, an estimated 26 million people across the West, the Plains, and the Southeast are experiencing peak-season heat this weekend, with some areas potentially reaching 108 degrees, roughly 5 to 10 degrees above typical mid-June levels. The West Coast is also bracing for temperatures 10 to 25 degrees above normal. NBC News notes that these temperature shifts could be linked to El Niño, a natural climate pattern that warms surface temperatures in the tropical Pacific and can amplify warming driven by climate change. The tournament, which features 48 teams across 16 cities in the US, Mexico, and Canada, faces various weather-related challenges. The Guardian reports that heat and humidity are the broadest challenges for players and spectators. While temperatures in Monterrey, Mexico, can be high, the humidity of the southeastern US is expected to produce the greatest heat strain. Fifa assesses heat-stress risk using the wet bulb globe temperature (WBGT) index; while many exercise physiologists consider 28C WBGT to be the level where high-exertion play becomes unsafe, Fifa’s own threshold for action is 32C. A 2025 study projected that 14 of the 16 host cities will exceed 28C at least some of the time. Other weather hazards include thunderstorms and tropical storms. The Guardian notes that thunderstorms disrupted an England warm-up in Orlando, and the National Hurricane Center is monitoring a low-pressure area over the Bay of Campeche with a small chance of tropical cyclone formation. Also, Mexico City presents challenges due to its altitude of approximately 2,240 metres, which reduces oxygen availability and can alter the flight of the ball. Meanwhile, NBC News reports that severe thunderstorms, including potential tornadoes and flash flooding, are threatening tens of millions of people across the central and eastern US.