US lightning protocols, requiring immediate suspension if strikes occur within eight miles of open stadiums and enforcing a 30-minute reset period, represent the dominant risk factor for weather-related halts at the 2026 World Cup. Summer thunderstorms common across US host cities amplify this threat, with FIFA deferring to local NOAA guidelines rather than tournament-specific cutoffs, potentially extending delays for hours on a case-by-case basis. Heat and humidity add pressure through mandatory three-minute hydration breaks in every half, though these rarely trigger full suspensions. Recent pre-tournament reporting from multiple outlets has heightened trader focus on these rules, while the expanded schedule and mix of covered versus open venues will determine exposure as group-stage matches begin.