U.S. record‑breaking heat wave sweeps West to East

A heat dome is driving a record‑breaking heat wave across the United States. Temperatures have already shattered all‑time highs in the West, with Billings, Montana reaching 111 °F (44 °C) and Salt Lake City, Utah hitting 109 °F (43 °C). The National Weather Service warned that the extreme heat is moving eastward, placing nearly 100 million Americans under heat‑alert warnings as it threatens major cities in the Northeast and Mid‑Atlantic, including Boston, New York, Philadelphia and Washington, where forecasts call for highs near 100 °F (38 °C).

Scientists from World Weather Attribution say the heat and humidity that accompanied the earlier July‑4 heat spell would have been “virtually impossible” without human‑caused climate change, and a strong El Niño is expected to amplify the pattern. The prolonged high‑pressure system also raises the risk of dry thunderstorms, wildfire spread, and strain on power grids as air‑conditioning demand spikes. Health officials stress the danger of heat‑related illnesses, especially for vulnerable populations, and advise staying indoors, staying hydrated and checking on neighbors.

Temperatures are expected to ease later in the week, but the event highlights how climate‑driven heat domes are becoming a recurring feature of U.S. summers.