150M Americans under heat alerts as extreme heat wave tightens grip, lingering over nation's 250th birthday
As millions of people go out to celebrate America's 250th birthday with beach days, fireworks and barbecues, feels-like temperatures between 100 and 110 degrees are forecast across the East Coast.
East Coast baking under intense holiday heat wave with 150 million affected
The July 4th festivities are going to be hot across the East Coast, as millions of Americans face a third day of excruciating temperatures capable of hitting triple-digits. The heat wave holds on through Sunday, when temperatures ease up slightly in the Northeast.
The core of a life-threatening heat dome has settled over the Eastern U.S., exposing more than 150 million people to extreme heat on July 4th, after some cities already shattered record-high temperatures on Friday.
Now, as millions of people go out to celebrate America's 250th birthday with beach days, fireworks and barbecues, feels-like temperatures between 100 and 110 degrees are forecast along the Northeast and Mid-Atlantic coasts on Saturday.
Washington, D.C., Richmond, Virginia, and Raleigh, North Carolina, are all expected to remain above 100 degrees on Independence Day.
WHAT IS A HEAT DOME AND HOW CAN IT AFFECT YOU DURING THE SUMMER MONTHS?
(FOX Weather)
Several states are at risk of hitting 100 degrees through Sunday, with 150 million people under heat alerts.
Within a heat dome, a strong high pressure system acts like a lid, trapping hot air near the ground and preventing cooler air from mixing in, allowing heat to build day after day.
According to NOAA, heat-related illnesses kill more Americans annually than any other type of extreme weather.
![WASHINGTON, DC - JULY 02: A man drinks from water bottle during the Great American State Fair on the National Mall on July 2, 2026 in Washington, DC.]()
Image 1 of 9WASHINGTON, DC - JULY 02: A man drinks from water bottle during the Great American State Fair on the National Mall on July 2, 2026 in Washington, DC. ((Photo by Alex Wong/Getty Images))
![PHILADELPHIA, PENNSYLVANIA- JULY 02: A fountain offers relief from the heat on July 02, 2026, in Philadelphia, Pennsylvania.]()
Image 2 of 9PHILADELPHIA, PENNSYLVANIA- JULY 02: A fountain offers relief from the heat on July 02, 2026, in Philadelphia, Pennsylvania. ( (Photo by Spencer Platt/Getty Images))
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Image 3 of 9WASHINGTON, DC - JULY 2: People walk near the Washington Monument which was closed due to a heat wave on July 2, 2026 in Washington, DC. Temperatures are expected to be around 100 degrees Fahrenheit over the next few days as celebrations for America's 250th birthday continue. (Photo by Kevin Carter/Getty Images) ( )
![A man enjoys a semi-frozen beverage while visiting "The Great American State Fair" during a heatwave in Washington, DC, on July 1, 2026.]()
Image 4 of 9A man enjoys a semi-frozen beverage while visiting "The Great American State Fair" during a heatwave in Washington, DC, on July 1, 2026. ((Photo by Alex WROBLEWSKI / AFP via Getty Images))
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Image 5 of 9Pedestrians carry umbrellas to shield themselves from the sun during high temperatures in Washington, DC, US, on Wednesday, July 1, 2026. (Photographer: Graeme Sloan/Bloomberg via Getty Images)
![CHICAGO, ILLINOIS - JUNE 29: People cool off at Crown Fountain in Millennium Park as temperatures topped 90 degrees on June 29, 2026 in Chicago, Illinois.]()
Image 6 of 9CHICAGO, ILLINOIS - JUNE 29: People cool off at Crown Fountain in Millennium Park as temperatures topped 90 degrees on June 29, 2026 in Chicago, Illinois. ((Photo by Scott Olson/Getty Images))
![NEW YORK CITY - JUNE 29: People cool off at Coney Island beach on June 29, 2026 in the Brooklyn borough of New York City.]()
Image 7 of 9NEW YORK CITY - JUNE 29: People cool off at Coney Island beach on June 29, 2026 in the Brooklyn borough of New York City. ((Photo by Spencer Platt/Getty Images))
![WASHINGTON, DC - JUNE 28: The U.S. Capitol building is seen the 110-foot "Freedom 250" Ferris wheel on the fourth day of the "Great American State Fair" on the National Mall as seen from the Washington Monument on June 28, 2026 in Washington, DC. The Freedom 250-backed Great American State Fair celebrating the 250th anniversary of the United States runs through July 10th.]()
Image 8 of 9WASHINGTON, DC - JUNE 28: The U.S. Capitol building is seen the 110-foot "Freedom 250" Ferris wheel on the fourth day of the "Great American State Fair" on the National Mall as seen from the Washington Monument on June 28, 2026 in Washington, DC. The Freedom 250-backed Great American State Fair celebrating the 250th anniversary of the United States runs through July 10th. ((Photo by Al Drago/Getty Images))
![NEW YORK, UNITED STATES - JUNE 29: People spend time at Washington Square Park during hot weather in New York City, United States, on June 29, 2026.]()
Image 9 of 9NEW YORK, UNITED STATES - JUNE 29: People spend time at Washington Square Park during hot weather in New York City, United States, on June 29, 2026. ((Photo by Selçuk Acar/Anadolu via Getty Images))
Local leaders throughout the eastern two-thirds of the country are advising people to be very cautious outdoors in what is the first major heat wave of the summer.
On Friday, organizers of the Great American State Fair on the National Mall made the decision to postpone all events until 5 p.m. due to the heat.
⚠️ Due to the heat, and in coordination with public safety officials, the Great American State Fair will be temporarily closed until 5:00 p.m. today.
— Freedom 250 (@Freedom250) July 3, 2026
The safety and well-being of our guests, volunteers, performers, vendors, and staff is our highest priority. Conditions are… pic.twitter.com/HV12RiMbu9
Dangerous heat intensifies over East Coast; Mid-Atlantic and Northeast could see hottest days on record
Washington, D.C. recorded high temperatures of 102 degrees on Friday, for the second day in a row.
New York City and Boston saw temps of 100. Meanwhile, Atlantic City, New Jersey recorded its second-hottest day ever at 105 degrees.
EXTREME HEAT SAFETY: HOW TO PREPARE AND STAY COOL DURING A HEAT WAVE
Tourists cool off in the shade during high temperatures in Washington, DC, US, on Friday, July 3, 2026.
(Valerie Plesch/Bloomberg / Getty Images)
Philadelphia tied a daily record Thursday, reaching 103 degrees, while Newark, New Jersey, hit 105 degrees for the first time since 2001.
The last time either New York or Philadelphia had back-to-back triple-digit days was in 2011. At one point Thursday morning, New York had the highest heat index in the country.
AMERICA 250: SEND US YOUR PHOTOS AND VIDEOS FROM ACROSS THE COUNTRY
(FOX Weather)
Triple-digit heat indices are expected to remain across the region through July 4, although the heat dome is shifting slightly south, allowing for more thunderstorms on July 4 across the region while the most intense heat remains over the Mid-Atlantic and parts of the Southeast.
WHAT WAS THE WEATHER LIKE ON THE FIRST EVER INDEPENDENCE DAY IN 1776?
The heat dome will finally begin to break down over the Mid-Atlantic on Sunday.
(FOX Weather)
Parts of the Ohio Valley remain under an Extreme HeatRisk, the highest category on NOAA and the CDC's extreme heat scale, indicating a long-duration heat wave with little or no overnight relief that can affect anyone without access to cooling and adequate hydration.
EXTREME HEAT SAFETY: RECOGNIZING SIGNS OF HEAT ILLNESS AND HOW TO TREAT IT
Extreme Heat Risk now covers the Mid-Atlantic and New York City.
(FOX Weather)
Heat safety experts also advise wearing loose, lightweight, light-colored clothing and frequently applying adequate sunscreen.
PHILADELPHIA, PENNSYLVANIA - JUNE 30: A re-enactor from Historic Philadelphia, Inc drinks water from period accurate canteen following a performance near Independence Hall on June 30, 2026 in Philadelphia, Pennsylvania. An extreme heat warning is in effect fir Philadelphia and the surrounding region for into the Fourth of July weekend as temperatures are expected to climb into the triple digits as a heat dome settles over much of the eastern and central U.S.
((Photo by Matthew Hatcher/Getty Images) / Getty Images)
Lightweight, breathable materials like linen, cotton and muslin are all great for hot temperatures.
Download the free FOX Weather app to stay up-to-date with the latest conditions and alerts to stay safe for the July 4th weekend.