More than 170 million Americans will face dangerous temperatures and humidity in the coming days as a heat dome develops over much of the U.S.

The first major heat wave of the year is expected to challenge record temperatures across the central and eastern states from the weekend into next week.

“It will be exceptionally warm at night with little relief once the sun goes down,” AccuWeather Chief On-Air Meteorologist Bernie Rayno warned. “Many urban areas may struggle to drop below 80 at night, and that can take a toll on the body without air conditioning.”

Sweltering heat was already impacting the West on Thursday and Friday – the longest day of the year – with highs peaking up to 104 degrees around Salt Lake City and Denver. One picture shared by the National Weather Service in Utah captured an infrared thermometer reading on a car’s dashboard at 165 degrees.

“NEVER leave children or pets inside a closed car on a hot day like this,” they said.

More than 170 million Americans will bake in extreme heat over the weekend and into next week due to a heat dome. High humidity in major cities will make conditions even more dangerous than normal (AP)

So, what is a heat dome, how does it form, and what should Americans be wary of in the upcoming days? Here’s what to know…

What is a heat dome?

A heat dome occurs when a large area of high pressure in the upper atmosphere acts as a reservoir that traps heat and humidity, Ricky Castro, a National Weather Service meteorologist in Illinois, said.

Warm surface air beneath a heat dome can linger for several days or even weeks, threatening human health.

Extreme heat is the leading cause of weather-related fatalities in the U.S.

“Extreme heat is tragically the leading cause of weather-related fatalities in America,” AccuWeather Chief Meteorologist Jonathan Porter said. “There is an amplified risk of heat-related illnesses because this is the first heat wave of the year for millions of people, and their bodies are not yet acclimated to this type of heat and humidity.”

How do they form?

Heat domes are tied to the jet stream. They trap heat over areas for days or even weeks (AFP via Getty Images)

Heat domes are typically linked to the behavior of the jet stream which, the National Oceanic and Atmospheric Administration explains, is a band of fast winds high in the atmosphere that move in meandering wavelike patterns. When the jet stream shifts northward, it moves slower and sinks. That allows for lower humdity and for the sun to create progressively hotter conditions on the ground.

However, air descending down mountains can also contribute to heat domes, as it warms even more.

Over cities, it is often warmer because pavement, buildings, and other types of hard surfaces tend to absorb and retain more heat.

“There may be more danger than a typical heat event, due to the longevity of near-record or record high nighttime lows and elevated heat index readings,” the National Weather Service’s Weather Prediction Center said.

Who will it impact this time?

A map shows heat across the U.S. next week. It will hit major cities in the Midwest, Southeast, and along the East Coast (AccuWeather)

Last summer, a heat dome “broiled” the Northeast and Midwest. This summer, it’s coming for big cities in the central U.S. and along the East Coast, along with horrible humidity that makes being outside even riskier.

AccuWeather expects that Philadelphia and Washington, D.C. will experience at least one week with highs at or above 90 degrees.

To the north, the Big Apple will also see multiple days of highs in the 90s, and areas around Manhattan will have temperatures exceeding 100 degrees.

Heading west, Chicagoans are bracing for three to five days of highs in the 90s, marking the “most intense heat wave Chicago has experienced in the last few years.”

Temperatures in Kansas City, Missouri, Oklahoma City, St. Louis, and Nashville will also leap above 90 degrees for multiple days.

To the Southeast, Atlanta and Charlotte are forecast to see temperatures between five and 15 degrees above the historical average.

So, how long will it last?

Human-caused climate change is making the planet hotter. It’s also making heat waves longer and more severe (AFP via Getty Images)

Temperatures are expected to dip a bit by mid-week and into the weekend, according to Fox Weather. Still, this is only the start of the summer season.

Human-caused climate change is making heat waves more frequent and severe. Last year was the hottest year on record, and the first heat advisory was issued in Alaska last week.

This will be the first stretch of true summertime weather for many in the eastern U.S.

“A lot of those folks have been saying, where’s summer? Well, buckle up, because it’s coming,” AccuWeather’s Tom Kines said.

With reporting from The Associated Press

US to Face Brutal Heatwave as Over One Hundred and Seventy Million Americans Facing Dangerous Temperatures, Tourism, Air Travel Brace for Major Chaos, New Update You Need to Know

A brutal heatwave is sweeping across the United States, and it’s doing more than just raising temperatures—it’s sparking a national travel emergency. With over one hundred and seventy million Americans now facing dangerous temperatures, the ripple effect is being felt in every corner of the country. From airports to hotels, from highways to beaches, tourism and air travel are bracing for major chaos. But just how serious is this crisis? And how fast is it unfolding?

This brutal heatwave is not an isolated event. It’s exploding across major metro areas and smashing long-standing records. But that’s only the beginning. As temperatures rise, infrastructure begins to falter. Energy grids are buckling. Transit systems are stalling. Airlines are scrambling. And families are canceling long-awaited vacations.

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The situation is growing more intense by the hour. The brutal heatwave continues to expand its grip, and the national travel emergency is deepening. Already, over one hundred and seventy million Americans are impacted. However, millions more are at risk if conditions worsen. The chaos isn’t just predicted—it’s happening now.

Meanwhile, tourism and air travel systems, already stretched by peak summer demand, are being pushed to the brink. Flights are being delayed. Airports are overwhelmed. Hotels are hitting power capacity. And dangerous temperatures continue to climb, with RealFeel highs topping 110 degrees in several states.

The travel emergency is real. The brutal heatwave is accelerating. And over one hundred and seventy million Americans are caught in its crosshairs. Will cities hold the line? Will cooling systems survive? Will the tourism sector adapt in time?

This is not just about the weather. This is about how a changing climate is testing our ability to move, connect, and escape. This is the kind of crisis that exposes cracks—and forces action.

As the heat continues to rise, the stakes grow higher. The entire travel industry is now in emergency mode. And the worst may still be ahead. Keep reading—this is one story you can’t afford to ignore.

America’s Summer of Heat: Travel Faces Crisis as Dangerous Temperatures Grip the Nation

A relentless heatwave has engulfed the central and eastern United States, putting over 170 million Americans under the threat of extreme temperatures and paralyzing humidity. This isn’t just another warm spell. This is a full-blown climate emergency sweeping into major tourism zones, airport hubs, and outdoor destinations at the height of the summer season.

RealFeel® temperatures are expected to soar above 110°F in many cities, with nighttime lows refusing to drop below 80°F. Urban areas are particularly vulnerable, creating a domino effect across travel infrastructure, energy systems, and public safety services. The tourism industry is facing a crucial test—how to adapt when summer turns dangerous.

Peak Heat Meets Peak Travel

The timing couldn’t be worse. The heatwave lands just after the summer solstice, during the longest days of the year. This is when Americans typically travel the most—booking beach holidays, heading to national parks, and flocking to amusement destinations.

However, the forecast is flipping the script. With heat domes locking in moisture and solar radiation, outdoor plans are being canceled, delayed, or shifted indoors. Resorts, campgrounds, and tour operators in affected regions are rushing to modify schedules and reinforce safety protocols. Many are now offering early morning or evening-only activities to reduce exposure risk.

Meanwhile, travel agencies report a surge in last-minute booking changes, with families shifting vacations to coastal cities, cooler mountain retreats, or canceling altogether due to health concerns.

Air Travel and Airports Hit Hard

Airlines are preparing for turbulence—literally and logistically. As tarmac temperatures spike, runway delays become more likely, especially at airports with high-density schedules like Chicago O’Hare, Atlanta, and New York’s JFK. Excessive heat impacts aircraft performance, gate operations, and even jet fuel efficiency.

Expect delayed departures, limited baggage handling operations, and overworked crews. Airport cooling systems are running at max capacity, and travelers are being warned to expect longer wait times at check-in and security due to staffing challenges worsened by the extreme heat.

More worrisome, power grid stress may result in localized blackouts, compromising airport systems and even delaying flights. Car rental companies in cities like St. Louis, Philadelphia, and Nashville are also reporting a spike in vehicle breakdowns as rental fleets overheat under prolonged use.

Hotel Industry Under Pressure

The hospitality sector is straining to keep up. In major cities like Washington D.C., Charlotte, and Oklahoma City, where highs are pushing 100°F for several days straight, hotels are battling energy surges as air conditioning units run nonstop. Some properties have begun rotating HVAC loads to prevent outages.

Hotel chains in tourist-heavy zones are proactively setting up hydration stations, providing emergency cooling kits, and adding shaded rest zones near pool areas. Health-conscious travelers are actively seeking hotels with medical readiness protocols and proximity to healthcare centers.

In response, booking platforms have added new filters for “climate control” and “heat-resilient features” to accommodate rising concern.

Cruise and Beach Warnings: Not All Waters Are Safe

While travelers fleeing inland heat are heading to Atlantic and Gulf Coast beaches, there’s another danger brewing—cold water shock. After weeks of unseasonably cloudy and cool weather, sea temperatures remain lower than expected. Jumping into icy waters during high external heat can cause muscle cramps, breathing issues, and sudden drowning risks.

Tourism officials across New England, New York, and New Jersey are ramping up public awareness campaigns to warn swimmers. Lifeguard services are on high alert, and advisories are being posted at major waterfront locations.

Travel Safety Now a Top Priority

Travel authorities are urging vacationers, especially those heading to theme parks, national monuments, and hiking trails, to adjust itineraries. Midday travel is now considered risky in many locations. Shuttle services and tour guides are adjusting times to avoid peak heat hours.

Cities such as Chicago, Atlanta, and New York are opening emergency cooling centers and offering guidance to tourists unfamiliar with extreme weather protocols. For international visitors, language barriers pose an additional safety risk, prompting multilingual advisories at airports and transport terminals.

Many outdoor festivals and summer events have already been canceled or rescheduled due to safety concerns. Vendors and local businesses relying on high summer foot traffic are bracing for a dip in revenue.

Market Impacts and Infrastructure Strain

The travel economy, already under pressure from post-pandemic inflation, is now facing rising operational costs. Hotels and airlines are increasing resource use to ensure climate control. Energy bills are surging, and small businesses in hospitality and transport are the most affected.

Meanwhile, data centers powering online travel bookings, airline operations, and weather monitoring tools are under increased cooling demands. Blackouts or equipment failure could paralyze reservation systems and disrupt real-time updates for travelers and agencies alike.

Moreover, ride-share services are facing longer wait times and reduced availability during midday hours, with drivers opting to pause during dangerous heat levels. Public transit systems in cities like Philadelphia and St. Louis are preparing backup plans as heat affects rail tracks and mechanical systems.

Human Toll and Health Crisis

Beyond logistics, the emotional and physical toll of this heatwave is massive. Families are dealing with sick children, overheated pets, and elderly relatives in vulnerable housing. Outdoor workers, including those in construction, delivery, landscaping, and hospitality, are among the most at risk.

With RealFeel® temps pushing 120°F in some areas, dehydration and heatstroke can set in rapidly. Local emergency services are stretched thin, responding to increasing calls from residents and tourists in distress.

Final Outlook: Prepare, Pause, and Pivot

This summer heatwave is more than a weather event—it’s a travel-altering crisis. Every segment of the industry, from airlines to amusement parks, is feeling the pressure to adapt in real time. For travelers, the message is clear: plan wisely, stay hydrated, and remain flexible.

As the heat dome lingers, tourism authorities are urging everyone to follow safety updates and heed travel advisories. Whether it’s a rescheduled flight, a canceled hike, or a modified hotel stay, taking early action can prevent emergencies.

The summer of 2025 is shaping up to be a turning point—where climate, health, and travel intersect in critical and very human ways. How the industry responds could define not just this season, but the future of safe travel under a warming world.

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Millions across the United States are bracing for a dramatic start to summer this week, as a powerful ‘heat dome’ is set to engulf vast swathes of the country, bringing with it stifling temperatures and oppressive humidity.

Forecasters have issued warnings of extreme temperature impacts, particularly highlighting the upcoming weekend for Nebraska, Illinois, Wisconsin, and Iowa, where residents can expect the most severe conditions.

This will be the first stretch of true summertime weather for many from Midwest to the East Coast, said Tom Kines, a meteorologist at the private weather company AccuWeather.

“A lot of those folks have been saying, where’s summer? Well, buckle up, because it’s coming,” said Kines. The humid conditions will make places that exceed 90 degrees Fahrenheit (30 degrees Celsius) feel as much as 20 degrees hotter, said Kines.

What is a heat dome?

A heat dome occurs when a large area of high pressure in the upper atmosphere acts as a reservoir that traps heat and humidity, said Ricky Castro, a National Weather Service meteorologist in Illinois.

According to the NWS Weather Prediction Center, daytime temperatures will be in the 90s Fahrenheit (30s Celsius) and overnight temperatures will only drop to the mid-70s Fahrenheit (mid-20s Celsius) from the Great Lakes to the East Coast during the heat wave that’s expected to last into next week.

Moisture blown northward from the Gulf of Mexico is fueling the muggy weather, said Jacob Asherman, a Weather Prediction Center meteorologist. This influx of Gulf moisture is fairly typical during late spring and summer, he said.

The heat will be widespread into next week. On Friday, Denver could reach 100°F (38°C), according to the weather service. Chicago temperatures could reach 96 degrees (36°C) on Sunday. On Tuesday, Washington, D.C., could see a high of 99°F (37°C) and New York Central Park could reach 96°F (36°C).

Several states in the Midwest could see dangerous temperature impacts over the weekend, according to a weather service measure. Parts of Nebraska and Kansas will be in the highest of four categories on the scale on Saturday, meaning that anyone without effective cooling or sufficient hydration could face health risks. On Sunday, Iowa, Wisconsin, Missouri and Illinois also see a category 4 rating.

Humidity is the amount of water vapor in the air, and the heat index is what the temperature feels like when the humidity outside is factored in, according to the weather service.

When humans sweat, it cools the body down because it absorbs and removes heat as it evaporates off the skin. The air is saturated with water on humid days, which makes it harder for sweat to evaporate. Hot and humid days can be dangerous when the body is unable to cool itself off and can exacerbate pre-existing health conditions and even lead to heat stroke.

Minimizing direct sun exposure, wearing loose and light-colored clothing, staying hydrated and spending time in air-conditioned spaces are ways to cool down during extreme heat, according to the NWS.

Some parts of the U.S., such as Phoenix, Arizona, are famously hot without the mugginess. Phoenix and nearby desert regions experience this so-called “dry heat” due to being located far away from large water bodies, mountains that block moist air masses and weather patterns that bring scarce precipitation.

Sweat evaporates faster in dry climates compared to humid ones. This can be dangerous because it is easy to underestimate how dehydrated you are, according to Johns Hopkins University and Johns Hopkins Health System.

In places such as Iowa, crops can affect the humidity in summer months. Plants feel the effects of hot weather and some people in the Midwest are familiar with “ corn sweat,” which is when crops move water to their leaves and other surfaces so it can evaporate, according to the Ohio State University.

Madison County, Iowa, farmer Ryan Marquardt said corn sweat is “not as bad as a sauna, but it definitely would have a sauna effect. It’s humid in there (the cornfield), so you’re gonna sweat.”

Cornfield contributions to the overall humidity are much lower compared to the humidity winds carry from the Gulf of Mexico, according to OSU.

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A brutal heat wave is in the forecast across the eastern United States, and it’s expected to bring several days of record high temperatures starting this weekend and into next week. The National Weather Service has called it “the first significant heat wave this season.”

The NWS said on Saturday that “major to extreme heat risk will spread into the Midwest and East Coast on Sunday, where anyone without effective cooling and/or adequate hydration will be affected. Little to no overnight relief will only exacerbate heat impacts.”

Over 140 million Americans will be under the highest-level extreme heat alerts by Sunday. Including heat advisories, the total number affected rises to 200 million. This marks one of the most expansive heat alert events ever, with major population centers from the Midwest to the Northeast under serious heat strain.

CBS News meteorologist Nikki Nolan said potential daily record highs are also forecast for parts of the Rockies and Plains on Saturday, then temperatures well into the 90s will reach the mid-Atlantic and Northeast and linger into next week.

Here’s what to know about the heat wave and how to stay safe.

Heat wave forecast maps

“Summer has taken its time arriving in the Northeast, but it’s coming in HOT,” the National Weather Service wrote Wednesday in a social media post. “Triple-digit heat indices will be common through next week, with oppressive humidity.”

The heat index is what the actual temperature feels like when it’s combined with relative humidity.

These maps show daily forecast highs across the country and their departures from average temperatures.

Saturday’s high temperatures across the U.S. CBS News

Sunday’s high temperatures across the U.S. CBS News

Monday’s high temperatures across the U.S. CBS News

Tuesday’s high temperatures across the U.S. CBS News

How long will the heat wave last?

The heat is expected to shift into the Midwest and Ohio Valley by the end of the weekend and arrive in the Northeast and mid-Atlantic on Sunday through the first half of next week.

Parts of the Northeast face a “High Risk” — a greater than 60% chance — of extreme heat through the middle of next week, according to the National Weather Service. Temperatures are forecast to be well into the 90s or even triple digits.

“I cannot emphasize this enough: extreme heat can be deadly,” New York Gov. Kathy Hochul warned. “The best way to stay safe is stay indoors, with air conditioning. This is not the time to start training for the marathon.”

What constitutes a heat wave?

A heat wave is a period of unusually hot weather that lasts more than two days, according to the National Weather Service.

It often, but not always, covers a wide area and can expose a large number of people to hazardous heat, which can be extremely dangerous for vulnerable people, including children and the elderly.

How to stay safe during a heat wave

The simplest way to way to avoid heat-related illnesses is to stay out of the sun and avoid extended time outdoors in extreme temperatures, experts say.

If strenuous outdoor activities are unavoidable, you should dress for the heat and wear lightweight, loose-fitting and light-colored clothing, the National Weather Service recommended. You should also stay hydrated by drinking plenty of water, even if you’re not thirsty.

It’s also important to be aware of any symptoms of overheating, which include muscle cramps, unusually heavy sweating, shortness of breath, dizziness, headaches, weakness or nausea, according to the Centers for Disease Control and Prevention. If you experience these symptoms, one major sign to seek care is if the symptoms don’t improve after getting into a cooler environment or hydrating, experts say.

contributed to this report.

Summer isn’t wasting any time.

A “significant and extremely dangerous heat wave” is sending temperatures soaring across much of the United States this weekend, with unhealthy levels of heat stretching from the Central Plains to the East Coast, according to forecasters with the Weather Prediction Center, and it is expected to continue into next week.

Temperatures at the end of spring have been relatively mild across the East, and Alex Lamers, a forecaster with the center, warned that those cooler-than-normal temperatures might mean that this sudden first burst of extreme heat is all the more dangerous because people in many areas have not acclimated to it yet.

“This will certainly be the first big heat wave of 2025 for the Northeast and Mid-Atlantic, as well as a large portion of the Midwest,” Mr. Lamers said.