It’s the hottest day in over a decade for parts of the East Coast. When will this extreme heat wave end?

By Mary Gilbert, CNN Meteorologist

(CNN) — A long-lasting extreme heat wave is reaching its dangerous crescendo Tuesday, likely bringing the hottest day in a decade to some major East Coast cities and putting millions of already fatigued Americans at risk.

The brutal conditions, spurred by a potent heat dome, are peaking Tuesday after building over the weekend in the central US and reaching levels rivaling summer’s hottest weather in the East Monday. It’s already taken a serious toll.

A St. Louis-area woman died after going without water or air conditioning for at least three days, police said Tuesday. The region has been gripped by searing heat that often felt above 100 degrees in recent days. The 55-year-old was discovered in her home Monday, according to St. Anne Police Chief Aaron Jimenez.

Two high school graduations in Paterson, New Jersey, in Monday’s sweltering conditions sent 16 people to the emergency room and over 150 people were evaluated for heat-related illnesses, Paterson Fire Chief Alejandro Alicea told CNN.

In Baltimore, an Amtrak train stalled in a tunnel and left passengers trapped in the heat for over an hour Monday afternoon.

“I honestly thought I was going to collapse on the train, and I’m fairly young and in good shape,” passenger Laura Evans told CNN, adding several of the train’s cars were without air conditioning even at the start of the journey.

In nearby Washington, DC, five people were taken to the hospital with heat-related illnesses Monday following a concert at Nationals Park, according to DC Fire and EMS. Another person was transported prior to the concert.

The extreme temperatures also prompted closures of some attractions, including the Washington Monument in the nation’s capital, which closed Monday and remained closed Tuesday due to an Extreme Heat Warning, according to an alert on the National Park Service website.

Nearly 160 million people in the eastern half of the US are under heat alerts Tuesday, according to the National Weather Service.

Heat remains the deadliest form of extreme weather in the US. Globally, heat waves are becoming more frequent, more severe and longer-lasting as the world warms due to human-caused climate change. Nighttime temperatures are taking the hardest hit from climate change, and are warming faster than daytime highs.

Extreme heat also takes a toll on infrastructure, causing materials like concrete and asphalt to expand and warp. Parts of key thoroughfares in Milwaukee and Green Bay, Wisconsin, suburbs were closed after buckling under searing heat Sunday, local officials said. More than 50 buckles were reported in the state, according to the Wisconsin Department of Transportation. Similar scenes unfolded in Cape Girardeau, Missouri, and the city warned more streets could crack as the heat persists.

Rail travel faced continued challenges amid scorching temperatures Tuesday. Several Amtrak trains in North Carolina were canceled due to “inclement conditions,” the company confirmed late Tuesday morning. Temperature-related speed restrictions were also in effect for multiple Amtrak lines in the Northeast.

Record-breaking heat continues

Tuesday will likely be the hottest day of the week for many in the East, but a level 4-of-4 extreme heat risk is in place through at least Thursday that stretches from the Midwest to the Mid-Atlantic and includes parts of the Northeast.

It feels more like July, summer’s hottest month, than June for many locations Tuesday as temperatures rise 15 to 20 degrees above normal. Triple-digit high temperatures will set in from the Carolinas north into southern New England – including every major I-95 city.

Tuesday in Boston could be hotter than it’s ever been in June. The forecast high of 101 degrees would break the June high temperature record and come within 3 degrees of the all-time record.

Philadelphia could also make a run for its all-time hottest June day – 102 degrees – with a forecast high of 101. A high of 101 degrees would also make Tuesday the city’s hottest-ever day this early in the summer. The city broke Monday’s daily high temperature record when it reached 99 degrees.

New York City could hit 100 degrees for the first time in over a decade on Tuesday. The city’s last triple-digit temperature happened on July 18, 2012, but it hasn’t been 100 degrees during June since 1966 – nearly 60 years. Like Philadelphia, a high of 100 degrees would make Tuesday New York’s hottest day this early in the season. Monday marked the city’s hottest day in nearly three years.

John F. Kennedy International Airport, in Queens, hit 102 degrees on Monday afternoon – the first time since 2013 and the first time ever in the month of June.

Washington, DC, is forecast to notch its first 100-degree day of the year on Tuesday – something that doesn’t typically happen until mid-July. A high of 101 degrees in the nation’s capital would break Tuesday’s daily record of 100 degrees.

When will it end?

Parts of the East Coast will start to see some relief from the historically hot weather Wednesday, though it’ll be a slow start.

Wednesday will still be very hot, but not quite as extreme for many. Record-breaking temperatures are possible, mainly in the mid-Atlantic, but triple-digit temperatures will be a thing of the past for the Northeast.

Heat more typical of late June will arrive on Thursday, but it will still be quite warm in the morning and prolong the agonizing wait for relief. Much of the Northeast will see highs in the 70s, with 80s and a few lingering 90s in the Mid-Atlantic.

Cooler, more typical, overnight low temperatures will finally reappear Friday in the East, and normal late-June heat will last through the weekend.

But temperatures are likely to creep back up above average early next week.

This week’s heat wave is likely only the opening act of a hot summer to come for the East. A hotter than normal summer is expected for the entire Lower 48, according to the Climate Prediction Center.

The-CNN-Wire
™ & © 2025 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.

CNN’s Rebekah Riess, Chris Boyette, Sarah Dewberry, Taylor Romine, Amanda Musa, Jillian Sykes, Tyler Ory and Luke Snyder contributed to this report