Heat Dome Covers Half of U.S., Forecast to Set Over 300 Daily High and Low Records by July 4

A heat dome covers more than half the United States and is forecast to produce more than 300 daily high and overnight low records by Saturday, July 4, 2026. Temperatures are expected to run 20 to 30 degrees above average through Saturday evening, according to CBS News meteorologist Nikki Nolan.

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ET Saturday. Mayor Zohran Mamdani said the conditions are extremely dangerous and recommended that residents stay inside and stay cool. The city is deploying vans staffed with nurses and paramedics to distribute water, electrolytes and sunscreen while also conducting wellness checks and transporting people to cooling centers.

Philadelphia shortened plans for its Salute to Independence parade on Friday because of the heat and maintains an extreme heat warning until 8 p.m. Saturday. In Nashville, temperatures could reach 101 degrees and feel like 114; heat patrols began distributing cold water to the homeless population during peak hours.

M. Saturday. A high of 101 degrees is forecast for July 4, which would exceed the previous record of 100 degrees set in 1919. Mayor Muriel Bowser urged residents and visitors to plan ahead, stay in the shade and limit time outdoors.

Destructive wildfires fueled by dry conditions and high winds are burning in parts of Utah and southern Colorado, where red flag warnings cite wind gusts up to 45 mph and relative humidity as low as 7 percent. Severe storms that tracked from the Plains to the Northeast are shifting southward and could affect the I-95 corridor over the holiday weekend.