Nearly 200 million Americans across 28 states are sizzling under a so-called heat dome this Fourth of July weekend.
Organizers canceled America's Independence Day Parade in Washington, D.C., saying the event scheduled for 10:30 a.m. on July 4 was called off because of extreme heat and an Extreme Heat Warning for the District of Columbia with heat index values expected between 110°F and 115°F.
Todd Marcocci, president of Under the Sun Productions Inc., the organizer of the parade, said, "This decision was made after extensive and careful consideration of the safety of our participants, spectators, and staff as the top priority." Organizers said the decision followed consultation with the National Park Service, the District of Columbia City Government and Freedom 250.
The Great American State Fair and the FIFA Fan Zone on the National Mall will open at noon Saturday, two hours later than originally planned, organizers announced Friday because of the extreme heat.
Shaquille Brewster reported from Chicago on June 29, 2026, that brutal hot weather is stretching across more than half the country, with record-setting temperatures and humidity targeting millions from the Midwest to the East Coast, and that massive wildfires in Utah and Colorado are sparking thick plumes of smoke visible from miles away.
The heat is expected to ramp up through the week, with temperatures soaring into the upper 90s and 100s and heat index values reaching 105 to 115 degrees Fahrenheit; cities in the risk zone include Boston, New York City, Philadelphia, Baltimore, Washington, D.C. and Chicago.
Major to extreme heat risk is expected Tuesday, with warm overnight temperatures offering little relief, and the heat will peak Thursday through Saturday for the Midwest, Great Lakes, mid-Atlantic and Northeast, with close to 100 new daily record highs expected by July Fourth.
Forecasters said a heat dome could trap more than half of the United States under dangerous heat through the holiday weekend and could produce heat index readings of 100 to 115 degrees from the Midwest to the East Coast, and that between daily high temperatures and warm overnight lows more than 300 records were expected to be set by Saturday.
New York City's heat index reached 106 degrees on Thursday, and the actual temperature in Central Park hit 100 degrees, marking the first triple-digit day there since 2012. New York City Mayor Zohran Mamdani, who activated a heat emergency plan with hundreds of cooling centers set to open on Wednesday, said, "My recommendation to all New Yorkers is to stay inside and stay cool." The city is deploying vans staffed with nurses and paramedics to hand out water, electrolytes and sunscreen, perform wellness checks, transport people to cooling centers and make in-home visits to vulnerable residents, and Mamdani urged New Yorkers "to stay inside and stay cool."
Washington and Raleigh will have highs of 103 later in the week with heat indexes of 108 and 107, respectively. The National Weather Service issued an extreme heat watch for Washington, D.C., for Thursday and Friday with forecast highs of 103, and a high of 101 is expected on Saturday, July 4, which would top the capital's highest recorded temperature for that date, 100, set in 1919. D.C. Mayor Muriel Bowser urged residents and visitors to plan ahead, stay in the shade and limit time outdoors.
Chicago Mayor Brandon Johnson urged residents during a news briefing to prepare for the extreme heat, saying, "If you can, stay inside with air conditioning on," and, "If you do not have air conditioning, keep your blinds closed, but windows slightly open." He said six community cooling centers will be open around the city and encouraged Chicagoans to stay hydrated and check on their more vulnerable neighbors.
Over the weekend numerous new wildfires erupted across the interior West, especially in Utah and Colorado, and three firefighters were killed while tackling fires on the Colorado-Utah border; they were identified as 27-year-old Sydney Watson, 27-year-old Nick Hutcherson and 38-year-old Emily Barker. Two more firefighters were injured and are receiving medical care.
U.S. Wildland Fire Service Chief Brian Fennessy said, "We mourn the loss of three firefighters who answered the call to protect others and made the ultimate sacrifice in service to their fellow citizens." The largest of the fires, the Cottonwood Fire in southwest Utah, is now more than 93,000 acres and remains zero percent contained, according to WatchDuty.com, and fire alerts remain in effect for the Four Corner states — Arizona, Colorado, New Mexico and Utah — as well as parts of Wyoming, South Dakota and Nebraska, with elevated risk increasing to critical on Tuesday for parts of Utah, Colorado, Arizona and New Mexico.
Record-setting heat is being blamed for dozens of deaths nationwide, with one count by news outlets putting suspected heat-related fatalities at 25 from the Deep South to the Midwest to the East Coast, officials said.
PowerOutage.us reported more than 900,000 utility customers without power on Saturday, with Michigan leading state totals at more than 305,000 customers without electricity, New Jersey reporting more than 124,000 outages and Missouri more than 100,000, according to the tracker.
Emergency workers and members of the National Guard were seen rendering aid to attendees at Salute to America 250 on the National Mall as severe thunderstorms moved overhead; officials measured the temperature of chairs in direct sun at about 160 degrees. More than 72 million people were under severe thunderstorm watches on Saturday, with forecasters warning storms could produce winds of 65 mph or greater and quarter-sized hail, and damaging wind gusts were reported across Nebraska and Iowa.
New Jersey's heat-related death toll rose from 19 to 22 on Saturday, Dalya Ewais, a state health department spokesperson, said. Health commissioner Dr. Raynard Washington said many of the dead were found in homes without air conditioning and that resources, including chillers and generators, were being sent to health care facilities "in distress." Washington said officials were working in some cases to evacuate patients from facilities where necessary.
Officials reported additional local heat-related deaths, including one in Cook County, Illinois, listed as organic cardiovascular disease with heat stress a contributing factor, and two deaths in Mississippi and Louisiana-area communities: Mitchell Ray Cooley, 74, of Hinds County, Mississippi, who died of heat exposure and had been the subject of a Silver Alert after he was reported missing, and Martha Irene Van Egmond, 83, who died in Bolton and whose death investigators attributed to the heat.
The heat surge disrupted travel and events in the capital as severe weather forced thousands of spectators to evacuate the National Mall area, with attendees directed to seek shelter in nearby buildings including the National Museum of African American History and Culture and the Ronald Reagan Building. Organizers reopened gates later in the evening and planned for President Donald Trump to deliver remarks at 11 p.m., after a schedule disruption caused by lightning and heavy clouds.
D.C. Fire Department reported more than four dozen patient contacts at the Fourth of July program on the Mall as medics and National Guard personnel aided people suffering heat-related ailments.
Two services under the European Union's Copernicus earth observation program said ocean surface temperatures hit record highs on June 21, with the Copernicus Climate Change Service reporting 20.86 degrees Celsius, or 69.54 degrees Fahrenheit, and the Copernicus Marine Service recording 21 degrees Celsius, or 69.8 Fahrenheit. Carlo Buontempo, director of the Copernicus Climate Change Service, said the rising temperatures could mark "the beginning of a new phase" and warned that "with ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months." Oceanographer Pierre-Yves Le Traon said, "It’s really worrying to see this trend," and Richard Allan, a professor of climate science at the University of Reading, said oceans absorb "more than around 90% of the excess energy" on earth that is primarily caused by burning fossil fuels.
The Copernicus announcements came as the National Weather Service warned of dangerous heat building across the central and eastern United States, and the agency said more than 46 million people across the country were under extreme heat alerts as of Wednesday with highs expected in the mid-to-upper 90s and some locations exceeding 100 degrees.
Fans at the New York New Jersey stadium were shown braving a heat dome over the East Coast, with temperatures in parts of the Northeast soaring to 38C; FIFA introduced hydration breaks during the match and the venue has no air conditioning installed.
An electric grid operator warned of potential power shortages amid the heat wave, and Energy Secretary Chris Wright issued emergency orders directing regional grid operator PJM to dispatch more power generation from various fossil fuel plants as needed despite environmental restrictions that are typically in place. The Trump administration said the orders are intended to maximize output for the mid-Atlantic power grid.
Orange County authorities said air conditioning failed on a bus carrying Junior ROTC cadets in Hamptonburgh, New York, resulting in multiple heat-related illnesses and prompting the transport of some cadets to hospitals as a precaution.
New York City said more than 200 teams of government workers and volunteers will check on homeless people and encourage them to get inside during the heat surge.
Dr. Alexander Azan of NYU Langone Health said high air temperatures combined with humidity are a dangerous combination because people in the Northeast often lack the level of acclimatization to respond appropriately to extreme heat, which can produce heat exhaustion and, in more severe cases, heat stroke. Vijay Limaye, a climate scientist at the Natural Resources Defense Council, said the concentration of concrete, asphalt and steel in cities helps retain heat and that the number on a phone may not reflect the true temperature profile outdoors.
Marc Savenor, owner of an ice company in Cambridge, Massachusetts, said demand has surged and he has hired extra drivers and added trucks and freezers to keep up with deliveries ahead of Fourth of July events. The American Kennel Club's Museum of the Dog in New York said it will allow visitors to bring their dogs to cool off through Sunday; Executive Director Christopher Bromson said he got the idea after seeing his own Newfoundland sprawled on the museum's cool floor. Taylor Harnist, whose Cincinnati business installs and repairs air conditioners, said he is keeping employees comfortable with breaks, water and electrolyte drinks and warned that attic spaces can reach temperatures of 145 degrees during the current heat. Jeff Schlegelmilch, an associate professor at Columbia University Climate School, said heat is one of the easiest weather extremes to attribute to climate change and pointed to longer, hotter summers and higher humidity as continuing trends.
With about 160 million people in 30 states under alert for extreme temperatures, the U.S. Department of Energy declared an emergency and Secretary of Energy Chris Wright issued an Energy Emergency Alert directing officials of PJM Interconnection in the Mid-Atlantic to take action to prevent blackouts and ensure essential operations such as hospitals remain functioning. Wright said, "Maintaining affordable, reliable, and secure power in the PJM service territory is non-negotiable." The alert went into effect at 11:59 p.m. Tuesday and will run through 11:59 p.m. Friday.
The emergency alert directs PJM to conserve energy by curtailing power to data centers that have backup generators and to other non-emergency facilities that use large amounts of electricity, and PJM said it is forecasting an electricity peak demand of 166,304 megawatts on Thursday, which would break a record set in 2006. Ramanan Krishnamoorti, vice president of energy and innovation at the University of Houston, said, "It's going to really strain the grid," and warned some utilities may have to implement rolling blackouts in localized areas. ISO-New England said it is expecting tight conditions and projects a peak demand of 25,850 megawatts on Thursday, below its record of 28,000 megawatts on Aug. 2, 2006, and that operators have tools to keep supply and demand in balance.
The National Oceanic and Atmospheric Administration declared El Niño underway in June and forecasters said it could be one of the strongest on record, a pattern expected to boost global temperatures over the next 12 to 18 months. New data released Tuesday showed the first six months of the year were the hottest ever measured for parts of eight western states, and forecasters said the current heat wave will be intensified by a massive drought affecting 45 states.
Water levels in the Colorado River basin are on pace for new record lows and have prompted mandatory water restrictions affecting Nevada and Arizona, officials said, and forecasters warned that later this summer water levels could fall below thresholds needed to continue operating major hydropower dams, including Hoover Dam. Colorado Gov. Jared Polis said, "Our communities are feeling the firsthand impacts of severe drought and imminent fire danger." Local officials said they have been preparing for months, sourcing additional equipment and seeking federal support from the U.S. Wildland Fire Service, a newly consolidated federal agency. Minnesota, Wisconsin and Michigan warned residents about a heightened potential for unsafe air quality from wildfire smoke this summer.
Medical experts warned that heat is a serious health threat and that certain medications can increase a person's vulnerability, including diuretics used for high blood pressure, anticholinergics, stimulants, ACE inhibitors, beta blockers and some psychiatric drugs. Physicians said symptoms of heatstroke may include neurological signs such as confusion and a body temperature that exceeds 103 F, and advised that anyone showing severe symptoms be taken to an emergency room immediately. Immediate cooling steps include getting the person into air conditioning or shade, misting or pouring water over the head and cooling the armpits and groin. Neil Gandhi, a physician at Houston Methodist Hospital, said that by the time a person feels thirsty they may already be 10% to 25% dehydrated. Researchers also noted higher temperatures are linked to increased emergency department visits for mental health conditions and addiction, and one study author estimated roughly an additional hundred young adults die by suicide each summer due to rising temperatures; people in crisis should contact the 988 lifeline.
Louisville Mayor Craig Greenberg discussed the city's response and precautions as a massive heat dome affected millions across the U.S.
Nearly 200 million people were under heat alerts as the heat wave intensified, and the extreme heat disrupted transportation and World Cup events across the Eastern United States.
The National Weather Service warned, "This level of rare and long-duration heat, with little or no overnight relief, affects anyone without effective cooling and/or adequate hydration."
By 9:00 a.m. EST on Thursday, temperatures were already close to 90 degrees Fahrenheit in Washington and New York City.
Meteorologist Rob Marciano said dozens of cities across the United States face triple-digit forecasts this Fourth of July weekend.
President Donald Trump is hosting America's 250th birthday celebrations and is expected to speak outside at a July 4 celebration on Saturday. He said, "By the way, on July 4th, it's going to be approximately 107 degrees out, and I'm gonna go and I'm gonna make a really long speech just to show that I can do anything."
The United States Capitol Police announced that only essential personnel would be allowed to attend a rehearsal for a July 4 concert in Washington because of concerns about members of the public gathering amid the excessive heat.
Temperatures in the Northeast are expected to drop a couple of degrees on July 4 with the threat of severe thunderstorms, with a more significant drop on Sunday and Monday as cooler air moves down from the north.
Pop star Taylor Swift and NFL player Travis Kelce are reportedly celebrating their wedding on Friday at Madison Square Garden in New York.
Organizers canceled a public World Cup watch party in Toronto for the Portugal and Croatia match, and heat warnings are in place across much of Quebec, including Montreal and Quebec City.
New York Gov. Kathy Hochul urged residents to conserve power as demand rose, saying, "Proactively conserve electricity if safe to do so by setting air conditioning units between 75 - 78 degrees and avoiding unnecessary appliance use." "I thank New Yorkers for taking these steps to reduce their usage and helping us keep the power on and protect the most vulnerable in our community," she said.
At least 26 Amtrak trains in the Northeast have been canceled since July 2, including trains servicing Baltimore, Philadelphia, New York City and Boston, and the cancellations have been attributed to temperature-related conditions.
At least 13,000 Americans have died from the heat since 2018.
Entry to the National Mall for a record-breaking fireworks show celebrating July 4 has been delayed, Freedom 250 organizers said Thursday.
An analysis by World Weather Attribution found the scorching heat this week would have been "virtually impossible" without the climate crisis and said such heatwaves are rare, occurring about once every 200 years even as the planet warms.
The analysis said that without roughly 1.4 C of planet warming, events like this would not have been expected to occur even once in many thousands of years, and it warned the heat dome is affecting large parts of the central and eastern United States and southern Canada. "The climate the country has today is fundamentally different to the one it had when the founding fathers signed the Declaration of Independence," Theodore Keeping, an extreme weather and wildfire researcher at Imperial College London, said in a press release.
Researchers also warned the heat could threaten Independence Day celebrations and World Cup matches, with France's match against Paraguay in Philadelphia on Saturday expected to see levels of extreme heat that a global players' union has previously said should trigger delay or postponement, and a Miami game between Cape Verde and Argentina scheduled the day before also expected to be played in potentially dangerous heat and humidity. "When a historic Fourth of July celebration is disrupted, and World Cup matches are played in conditions that are unsafe for players and fans, it shouldn't take another scientific study to wake people up," Friederike Otto, a professor of climate science at the Centre for Environmental Policy at Imperial College London, said in the release.
More than 100 people required medical evaluation and care after a mass casualty event at the Reading Railroad Outer Station in Muhlenberg Township on Thursday, the Blandon Fire Company QRS said, and initial reports said the incident stemmed from heat-related emergencies. First responders set up tents and cooling buses at Muhlenberg Park around 2:00 p.m. Thursday, and dozens of ambulances were on the ground as emergency resources were mobilized from multiple jurisdictions across Berks, Lancaster, Chester and Schuylkill counties, Blandon Fire Company QRS said.
Union Pacific said the Big Boy locomotive drawing crowds was running nearly one hour behind schedule because of the heat, and the locomotive was making a stop in Reading in honor of America's 250th birthday. Authorities have not released the exact number of people impacted or their conditions, Blandon Fire Company QRS said.
The city's emergency management agency said multiple shark sightings were reported Thursday at Rockaway Beach, New York City's largest beach, prompting officials to warn beachgoers to expect "intermittent closures" as the heat dome pushed the heat index above 105 degrees. The city announced Wednesday that additional cooling centers will be open through July 5, including the Jacob Javits Convention Center, a 3.4 million square foot facility, and officials said mobile cooling vans will continue to provide wellness checks and services.
Festivities commemorating the nation's 250th anniversary kicked into higher gear on Friday as celebrations around the country balanced public events with safety measures for extreme heat.
President Donald Trump will travel to South Dakota to deliver a speech and watch fireworks at Mount Rushmore, and he is also scheduled to deliver another speech at the National Mall in Washington before what organizers call a historically massive fireworks show.
New York Mayor Zohran Mamdani delivered an address at City Hall on Friday marking the 250th anniversary and said, "The frontier may be closed, we may have walked on the moon, but the work of fulfilling the values first enshrined in the Declaration of Independence, that work endures, and it belongs to us all."
Organizers of the Capitol Fourth concert said the gates will open to the public later than usual on Friday, at 7 p.m. EDT, and officials said they were adding water stations along with cooling resources and medical support for events in Washington.
In Philadelphia, the Salute to Independence Semiquincentennial Parade was canceled because of the weather.
An April survey from the AP-NORC Center for Public Affairs Research found about four in 10 U.S. adults said they feel "proud" about the country's 250th anniversary, while roughly three in 10 said "excited" best described their feelings.
Auto technician Joe Fuqua-Bejarano in Topeka, Kansas, said resilience is what he sees in people preparing for the holiday, and he urged people to "find unity somewhere, whether that’s in laughter or perseverance, and keep everybody cool." Christina Zhou, a 25-year-old research assistant from Cambridge, Massachusetts, said she would focus on local activities and "think about just things that are happening locally."
The CDC reported "extremely high rates of heat-related illness" in regions across the Northeast on Thursday as emergency departments saw surging visits related to the multiday heat wave.
The Berks County coroner's office said a 68-year-old man died after trimming bushes on July 2 in Bethel Township, Pennsylvania, and that the cause of death was a heart attack from strain "due to heat exhaustion."
Washington, D.C., reached 102 degrees on Friday, surpassing a previous 101-degree mark set in 1872, and Ronald Reagan Washington National Airport reached 102 degrees on Thursday.
LaGuardia Airport recorded a midnight temperature of 94 degrees early Friday, breaking the previous midnight record of 93 degrees set on July 18, 2013.
Philadelphia climbed to 103 degrees on Thursday, tying a daily high-temperature record that had stood since 1901 and marking the city's fourth-warmest day on record.
D.C. Fire & EMS said there were 45 patient contacts and 16 patient transports at the Great American State Fair on the National Mall.
Mayor Frank Velez of Belleville, New Jersey, rescheduled the city's fireworks for next year, saying, "While we're disappointed we couldn't celebrate together tonight, your safety will always come first."
A 79-year-old woman experienced a heat-related emergency at the "Salute to America 250 Celebration & Fireworks" and was transported to a local hospital, the National Special Security Event Joint Information Center said.
Three children died after a boat capsized on Geneva Lake during a sudden and severe storm, police said. Officials said the privately owned motorboat carrying 10 occupants tried to race to safety before it was overwhelmed by wind and waves; six adults and a child were rescued, and police said the three children recovered from the lake were unresponsive when found. Officials said all four children on board were wearing life jackets.
Lake Geneva Mayor Todd Krause declared an emergency and officials said a person suffered minor injuries after being struck by a falling tree during the storm.
The National Weather Service's Weather Prediction Center said Atlantic City set its highest temperature for July at 105 degrees.
Storms produced wind gusts of up to 70 mph in Perth Amboy, New Jersey, damaging or uprooting hundreds of trees and prompting train cancellations and delays.
D.C. Homeland Security and Emergency Management warned, "A severe thunderstorm is occurring near the National Mall. Seek shelter immediately. Do not wait. Follow instructions from event staff and public safety officials on site."
Calls to emergency medical services climbed in Washington, D.C., as the city sweltered under the extreme heat.
Organizers said military flyovers will occur every hour between 13:15 local time (17:15 GMT) and sunset and that the president's new Air Force One will be featured in one of the formations.
Organizers said the fireworks display planned over Washington will use about 850,000 fireworks launched from 10 sites across the city, including eight barges on the Potomac, will last roughly 40 minutes and is intended to set a Guinness World Record for the largest official fireworks show.
Organizers said the Washington event is due to begin at 7 p.m. local time.
Several music acts announced for the Washington event dropped out soon after being revealed, organizers said.
The city's main Independence Day parade was canceled, though a smaller parade rolled along in the Capitol Hill neighborhood on the morning of the holiday as onlookers sought shade.
The National Weather Service issued a severe thunderstorm watch for the Washington, D.C., area and said frequent lightning was possible; the advisory was in place until 10 p.m. local time.
Annapolis' emergency services department said it had canceled its Independence Day parade and a concert and warned that a planned pyrotechnics display may be delayed.
Tracker PowerOutage reported nearly 750,000 people without power in the eastern U.S., including more than 350,000 in Michigan and about 150,000 in New Jersey, and energy company DTE said winds over 60 mph in Michigan on Friday evening caused widespread outages.
Officials in Philadelphia buried a time capsule near Independence Hall to be reopened on July 4, 2276, and said it includes a diamond mined in Alaska, poems from several states, a set of gambling chips from Nevada, a vial of sand from New Mexico and a printout of an AI's answer. Jennifer Condon, executive vice president of America 250, said, "There is something profoundly humbling about this task."
President Donald Trump posted on Truth Social, "Despite the heat, which isn't as bad as predicted, the crowds in DC are incredible."
By midafternoon, lead weather presenter Ben Rich said Baltimore had reached 104°F and Washington, D.C., had climbed above 100°F, and officials in several Colorado communities including Colorado Springs, Douglas County, Arvada, Durango and Vail called off firework displays because of dry conditions and concerns about high winds.