Key keywords: July Fourth DC region events, 2024 DC Independence Day celebrations, National Mall fireworks disruption, hot stormy weather DC July 4, DC severe thunderstorm alerts, July Fourth event cancellations, DC extreme heat advisory, Fourth of July public safety guidelines Severe hot and stormy weather upended nearly all planned July Fourth celebrations across the Washington, DC metropolitan area on Thursday, leaving tens of thousands of attendees disappointed, local vendors with steep financial losses, and emergency crews working around the clock to respond to weather-related incidents. The National Weather Service (NWS) issued a level 3 excessive heat advisory for the entire DC region early on July 4, warning that high humidity would push heat index values to as high as 107 degrees Fahrenheit (41.7 degrees Celsius) by mid-afternoon, with a 90% chance of severe thunderstorms bringing damaging winds, penny-sized hail, and frequent lightning starting at 6 p.m. By 3 p.m., DC Fire and EMS had already responded to 42 confirmed heat-related emergencies, including 11 hospitalizations, among crowds that had gathered on the National Mall as early as 8 a.m. to secure spots for the annual fireworks display, which typically draws more than 300,000 attendees each year. As the first line of thunderstorms moved into the District shortly after 5:30 p.m., the National Park Service (NPS) issued an immediate mandatory evacuation order for the entire National Mall, directing attendees to nearby underground metro stations, government buildings, and designated public shelters to avoid lightning strikes and wind damage. Officials announced shortly after the evacuation that the flagship National Mall fireworks show would be rescheduled to July 5 at 9:15 p.m., with all pre-event security screenings waived for attendees who had already cleared checks on July 4. Disruptions extended far beyond the National Mall: dozens of suburban events in northern Virginia and suburban Maryland, including the annual Arlington County Independence Day parade, Alexandria’s waterfront fireworks display, and Bethesda’s community block party, were either cut short or fully canceled for the day. Local food vendors who had spent thousands of dollars prepping stock for the holiday crowds reported average losses of between $2,500 and $6,000, as most foot traffic vanished within 15 minutes of the evacuation order being issued. NPS and DC emergency officials have reminded residents and visitors planning to attend the rescheduled fireworks to monitor weather updates closely, bring sufficient water and sun protection, and follow all directions from on-site staff to prioritize personal safety.