America250: How the US heatwave will affect Fourth of July celebrations

From Washington to LA, how plans to mark the Unites States’ 250th anniversary could be disrupted by extreme heat.The Great American State Fair is being held on the National Mall in Washington, DC [Allison Robbert/AP Photo]Published On 4 Jul 2026The United States is about to celebrate its 250th birthday, but as millions across the country prepare to gather this weekend for parades, concerts and festivals, an intense heat wave has settled over much of the eastern US.Officials across the region are warning that the extreme heat could pose serious health risks over the Fourth of July weekend.Recommended Stories list of 3 itemslist 1 of 3Hottest June on record in France as heatwave deaths rise to alarming levelslist 2 of 3US heatwave raises alarms over AI data centre energy demandslist 3 of 3Massive wildfire spreads in Portugal amid extreme heat and strong windend of listHere’s what you need to know about how the weather will affect the celebrations.What is America’s 250th anniversary?It has been 250 years since the United States adopted the Declaration of Independence on July 4, 1776. Unlike a typical Independence Day, this year’s celebrations are unfolding on a much bigger scale, capping years of preparation and planning.Landing in the midst of a highly polarised moment in American politics, planning for the anniversary has also been contentious.A decade ago, Congress tasked a bipartisan commission known as America250 with organising the celebrations.But last year, US President Donald Trump issued an executive order to put his own “Freedom 250” planning committee in charge of many of the anniversary’s marquee events, including the Great American State Fair on the National Mall.Initially, a variety of musicians were announced as performers for the fair, including country singer Martina McBride, the soul group The Commodores and the pop duo Milli Vanilli. But many withdrew in late May and early June over concerns over the fair’s affiliation with Trump.Last week, in lieu of the performers, the US president delivered a speech to open the fair, billing himself as the “Number One Attraction anywhere in the World”.He has also promised to mark the July 4 holiday in Washington, DC, with “the most spectacular TRUMP RALLY of them all”.The Department of Labor building in Washington, DC, displays US flags on the eve of July 4th festivities [Joe Raedle/Getty Images/AFP]What will celebrations look like across the country?Among thousands of smaller, locally organised celebrations nationwide — including historical reenactments, picnics, concerts and fireworks displays — some of the highest-profile events include: Washington, DC: Hundreds of thousands are expected to arrive in the city, where the Great American State Fair will be held along the National Mall, the 2.5 km (1.5 mile) promenade linking the US Capitol to the Washington Monument. It will feature state pavilions, food, live music and a Ferris wheel. Trump has also promised “the largest fireworks show in history.” Around one million people attended the fireworks display for the US’s bicentennial anniversary in 1976. Los Angeles: As part of its America’s Block Party event, America250 will hold a benefit concert hosted by Queen Latifah, featuring artists such as Chris Stapleton, Maren Morris and the Smashing Pumpkins. Philadelphia: The city where the Declaration of Independence was signed is hosting one of the country’s biggest commemorations, including the burial of a 400kg (900 pounds) time capsule, containing artefacts from across the country, meant to be opened at the next semiquincentennial in 250 years. New York: More than 40 tall ships are expected to sail into New York Harbour with almost 20,000 sailors aboard, while more than 200 aircraft fly overhead. Boston: Celebrations will include the annual Boston Pops Fireworks Spectacular — a free concert followed by a fireworks display — and a public reading of the Declaration of Independence from the balcony where it was first read aloud to Bostonians in 1776. How will the heat affect celebrations?Some celebrations are already being disrupted, with organisers forced to adapt to extreme heat.On Friday, the Great American State Fair temporarily closed as temperatures reached over 39 degrees Celsius (102 degrees Fahrenheit) in parts of Washington, DC.But the capital was not the only area affected by the extreme heat.In Philadelphia, for example, officials announced that the Salute to Independence Semiquincentennial Parade was cancelled, after initially planning to shorten the route to mitigate heat-related risks.A celebration in Pennsylvania’s Lower Windsor Township was also rescheduled for July 8, while in nearby Norristown, officials cancelled another parade, citing safety concerns.The heat is also affecting transportation. Amtrak announced several train cancellations in the northeast region and warned that other trains could face delays due to high temperatures, which can affect railway infrastructure.“Extreme heat can cause rail, bridge and overhead wires to expand,” it said in a statement on Thursday. “As a precaution, Amtrak may enact heat restrictions, which can require locomotive engineers to operate trains at lower speeds, resulting in potential delays.”What will it actually feel like outside?While air temperatures in cities such as Philadelphia and Boston are expected to reach around 38 degrees Celsius (100 degrees Fahrenheit), high humidity can make it feel significantly hotter.That’s because humidity makes it harder for sweat to evaporate and cool the body. Weather agencies use the heat index, often called the “feels like” temperature, to estimate what people will actually be experiencing.Experts also warn that cities can become even hotter than forecasts suggest as concrete, asphalt and steel absorb heat.“The number on your phone may actually not reflect the true temperature profile that you’re going out into,” Vijay Limaye, a climate scientist at the Natural Resources Defense Council, told The Associated Press.What precautions are officials taking?Aside from changing or cancelling some Fourth of July events, cities across the eastern United States are rolling out broader measures to help people cope with the heat.In New York City, for example, more than 200 teams of government workers and volunteers are checking on homeless residents and directing people to hundreds of cooling centres, including public buildings, mobile cooling vans and outdoor sites equipped with misting fans.Mayor Zohran Mamdani urged people to stay inside and avoid “extraordinary temperatures”. He also asked residents to set their air conditioners to 26 degrees Celsius (78 Fahrenheit) to avoid straining the power grid.Boston is offering residents free admission to several air-conditioned museums, while Providence, Rhode Island, has extended hours at public pools and water parks.How can people stay safe?The National Weather Service (NWS) recommends drinking a lot of water, even if you don’t feel thirsty, especially if you’re spending an extended amount of time outside and taking hourly breaks in shade or air conditioning.Health authorities also urge people to occasionally check in on seniors and other vulnerable populations.Alcohol can make dehydration worse, so experts also recommend limiting drinking during long outdoor events.Signs of heat illness include cramping, rapid pulse, heavy sweating, hot red skin, dizziness, confusion, nausea and vomiting, according to the NWS. If you see any of those warning signs, seek medical attention immediately.