Americans celebrating Fourth of July face scorcher

Tens of millions of Americans in the Midwest and on the East coast will face brutally hot temperatures and stifling humidity as they celebrate the Fourth of July holiday on Wednesday, the National Weather Service (NWS) said.

Heat advisories and excessive heat warnings were in effect through Wednesday night, with heat index values – which combine temperature and humidity – in major U.S. cities such as New York City and Chicago expected to reach well above 90 degrees Fahrenheit (32°C).

At least four people have died due to the heat over the last week, including a Pennsylvania woman who died while working in her garden on Saturday and a man who was running a race in New York on Sunday, CNN reported.

Photos: Blazing-hot heat wave hits New York City in June/July 2018

For the Fourth of July holiday, Dan Petersen, an NWS meteorologist, warned people celebrating outside to remain in the shade and drink plenty of fluids.

"Anyone outside in locations with expanded areas of heat is going to have to take precautions," Petersen said. "This is the peak of summer – the hottest time of the year."

Later this week, a storm front is expected to roll through and cool down the eastern seaboard for the weekend, Petersen said, providing relief to Washington, D.C. and Philadelphia on Friday night before heading down to the Carolinas.

In a reversal of normal patterns, Petersen said, the hot weather will head west, hitting the central United States late in the week before reaching Los Angeles and San Diego on Friday. (Reporting by Brendan O'Brien in Milwaukee Editing by Gareth Jones)