A severe heat wave has impacted Fourth of July festivities across the central and eastern United States, leading to cancellations and postponements of numerous events. The Great American State Fair in Washington D.C. was temporarily closed, and the National Park Service’s Independence Day Parade was canceled due to dangerously high temperatures, potentially reaching 115°F. The heatwave, caused by a “heat dome” trapping hot air, has also placed significant strain on power grids. PJM, a major grid operator, initiated emergency conservation programs to address generator outages and increased demand. Con Edison in New York reported approximately 17,000 customers without power late Friday. The extreme weather conditions pose risks to public safety and infrastructure across several states.