US Heat Dome Disrupts July 4 Events; PJM Urges Power Cuts as 185 Million Face Heat Alerts

A “heat dome” blanketing the US as the country marks its 250th Independence Day is driving extreme temperatures across the densely populated East Coast, with Philadelphia forecast to top 38°C on July 4 and a heat index reaching 43.3°C, prompting the city to cancel events including the “Salute to Independence Parade,” according to Jiemian News. Since last Thursday, the region has set more than 30 daily high-temperature records; Washington, DC broke a more-than-120-year record for the period and is expected to see its hottest Independence Day on record, leading officials in multiple locations to cancel or postpone dozens of parades, concerts and fireworks shows.

The US National Weather Service said more than 185 million people were under heat alerts on July 3. PJM, the largest US power grid operator, asked participants in its emergency energy-saving program to reduce electricity use to manage surging demand. The report also cited Europe’s recent heatwave impacts, including more than 1,300 heat-related excess deaths since late June, and noted research warning that several US World Cup host cities face very high heat risk.