WASHINGTON — Extreme heat alerts covered about 180 million Americans on Friday as a dangerous heat dome persisted across much of the central and eastern United States ahead of the July 4 holiday weekend.
The National Weather Service said more than 180 million people were under extreme heat warnings or heat advisories early Friday, with triple-digit temperatures and high humidity creating life-threatening conditions in many areas.
Forecasters warned of heat indices reaching 105-113 degrees Fahrenheit (41-45 Celsius) in parts of the Midwest, Mid-Atlantic and Northeast, with some locations expected to approach or break daily and monthly records. The oppressive heat, which began in late June, was forecast to continue through the holiday weekend.
The heat dome has already produced record temperatures, including in Washington, D.C., where the city shattered a 126-year-old mark on July 2. Similar records or ties were reported in surrounding areas including Baltimore, Philadelphia and Boston.
Officials urged residents to limit outdoor activity during peak heat hours, stay hydrated and check on vulnerable populations, including the elderly and those without air conditioning. Power grid operators were on alert for high demand, with some emergency measures implemented to maintain reliability.
The National Weather Service described the event as part of an ongoing 2026 North American heat wave affecting nearly half the U.S. population. Some relief is possible in certain areas by early next week, but conditions were expected to remain hazardous through Sunday.
The story is developing.
