Much of U.S. Bakes as Some Cities Break Temperature Records (2024)

For much of the nation, no relief from the heat is expected this weekend.

In New York City, officials and utility providers are bracing the city for the lingering heat, which is expected to reach a heat index of 103 degrees between Saturday and Sunday. Already, the city has recorded temperatures it hasn’t seen in almost two years, with Central Park hitting 94 degrees on Friday.

Elevated temperatures raise the risk of heat-related power outages, but power grids in New York and across the country so far have largely held up.

Still, hazardous conditions remain. In Manhattan and cities including Indianapolis and Cincinnati, residents faced the highest level of health risk from the heat, according to a gauge by the National Weather Service and the Centers for Disease Control and Prevention. Their measurement, called HeatRisk, rates the danger in an area on a scale from zero to 4 based on factors that include the duration of the heat and how unusual it is for this time of year.

C.D.C. data also showed that heat-related illnesses spiked this week in regions like the Northeast and the Midwest — areas that have been hit the hardest by the heat wave.

Though the heat wave will not fade over the weekend, conditions are expected to cool slightly on Monday. But even if they do, the country won’t be in the clear: Forecasters expect temperatures to still hover above average in the Mid-Atlantic States through the middle of next week.

Heat-related illnesses spiked in some regions this week, C.D.C. data shows.

In the Mid-Atlantic, including the Washington area and Philadelphia, the number of visits climbed from 290 on Monday, the first day of the heat wave, to 1,150 on Saturday. That was the highest rate anywhere in the country all week. On Saturday and Sunday, several temperature records were broken in Washington, Baltimore and Philadelphia.

Data also showed a spike in the region that includes Iowa and Missouri, with 1,077 visits on Saturday, up from 267 on Monday. On Saturday, the temperature in Kansas City, Mo., reached 95 degrees, 10 degrees above average for this time of year.

Earlier in the week, as New England states sweltered under record-breaking temperatures, the number of visits climbed from 57 per 100,000 on Monday, the first day of the heat wave, to 848 on Thursday.

The region is less acclimated to having high temperatures this time of year than others, and places like Boston and Hartford, Conn., had record temperatures. Caribou, Maine, reached 96 degrees this week, tying the highest temperature ever recorded there.

Much of the Midwest also had more heat-related emergency room visits than usual, with such trips reaching a peak of 632 visits on Wednesday. Chicago hit a record high of 97 degrees on Monday.

Areas around New York and New Jersey also saw a surge in heat-related medical issues this week, going up to 537 heat-related emergency room visits on Friday, from 141 on Monday. New York City reached daily temperatures it hadn’t experienced in almost two years, going up to 94 degrees in Central Park on Friday.

Deaths resulting from extreme heat have been on the rise in the country in the past few years. The C.D.C. recorded about 2,300 heat-related deaths in 2023, up from approximately 1,700 in 2022 and about 1,600 in 2021.

Global warming has been making heat waves hotter, more frequent and longer lasting. And the longer a heat wave, the more health risks people face because each additional day of extreme heat further strains the body.

Temperatures in New England fell on Friday, but the Mid-Atlantic continued to bake through Sunday. By Monday, cooler temperatures are expected along the populous Interstate 95 corridor on the East Coast, but the National Weather Service predicts intense — and potentially dangerous — heat for parts of the South and the Plains throughout the upcoming week.

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The heat couldn’t stop a parade of mermaids on Coney Island.

“It’s taken us half an hour to walk this far,” the younger Ms. McDermott, an artist and a self-styled “professional eccentric,” said. “Only because we look as good as we do,” her mother added.

The pair said they had been marching in Coney Island’s pageantry of aquatic weirdness for several years, and that they had not been deterred by a citywide heat advisory. The temperature was already 86 and climbing as costumed marchers and spectators assembled under a cloudless blue sky.

But the mood was upbeat as DJs on floats tested their speakers and marching bands tuned up near the staging area at Surf Avenue and West 21st Street.

On a side street, Elijah Thomas of Harlem stood under the shade of a tree with several of his bandmates from Honk NYC!, a nonprofit that promotes brass and percussive street music and participates regularly in the parade.

Mr. Thomas, 24, spoke about the inspiration that the Mermaid Parade, founded in 1983, drew from the street marching culture of Mardi Gras in New Orleans. A repeat performer at the Mermaid Parade, Mr. Thomas said he had come for “the pageantry, the community music making and the parading.”

Nearby on Surf Avenue, Dmitry Brill — better known as DJ Dmitry of the pop group Deee-Lite — did a soundcheck with his laptop mounted on a small float. The float was adorned with the name of a Berlin, Germany-based band he is producing, Nauti Siren, whose members were using their first turn at the parade to roll out a new single entitled, aptly enough, “Mermaid of the Year.”

Brill, 60, said this was his first time officially participating in the parade, though he attended it once as a spectator in the late 1980s.

Another first-time marcher, Leah King, wore a gold tiara, a bikini top and an eight-legged octopus skirt in the style of Ursula, the queenly villainess from Disney’s “The Little Mermaid.” She wielded a gold-tipped trident as she, too, stopped repeatedly for photographs.

“I’m a cosplayer,” Ms. King, 40, said. “I was made for this. The mermaid is my alter ego.”

The parade kicked off with this year’s official King Neptune and Mermaid Queen — New York husband and wife artists Joe Coleman and Whitney Ward — riding in an electric tricycle under a canopy trimmed with gold. Mermaids, ship captains, pirates and people dressed as various forms of marine life trailed behind, followed by musical floats and bands playing techno and pop hits.

The procession rolled east along Surf Avenue past rows of cheering spectators, past the original Nathan’s hot dog emporium, and toward its eventual turn onto the Boardwalk, and on to its end point at the towering metal Parachute Jump, one of Coney Island’s most recognizable landmarks.

Jenni Bowman, 42, of Brooklyn, watched with friends behind barricade fencing from under the shade of a four-pole party tent.

Ms. Bowman said she comes to the parade for its offbeat celebration of “ocean mythology,” as well as for its artistry. “It’s an art parade,” she said. “The people of New York City are incredible. This is a representation of their artistry and their love for this community.”

Acknowledging the weather, Bowman added, “My friends and I bought a tent to stay in the shade because we want to be hydrated and safe.”

As it happened, the weather eased as the afternoon wore on and a light cloud cover helped keep the temperature below 90 degrees.

Thousands of Michigan residents weather days without power during the heat wave.

Three days after the outage, about 7,000 customers are still without power, according to DTE Energy, a Detroit-based utilities company that serves the area. Detroit has suffered temperatures in the 90s since the heat wave began on Monday. The heat index, a measure of how conditions feel with humidity factored in, reached 95 degrees on Saturday afternoon.

Ms. Brenz’s biggest concern was keeping herself and her cat, Bubba, safe from the sweltering conditions during the outage. She closed her windows, drew the blinds and refrained from showering to keep her house in Berkley cool.

“It was the little things I had to be aware of to keep me and my cat safe,” said Ms. Brenz, who works for a nonprofit.

Deb Dworkin, a 52-year-old human resources manager, lives in a bungalow in Berkley. She said her upstairs bedroom got “crazy hot” during the outage. She slept on her couch for two days, using a battery-powered travel fan and a neck towel filled with ice cubes.

“I probably looked ridiculous,” she said.

Michael Reiterman, a 25-year-old assistant financial planner who lives in New Baltimore, tried similar remedies in his home, including shutting the blinds to keep out the heat. But his ultimate solution was to shuttle between his home, which had outages intermittently, and his fiancée’s house, which maintained power through the week.

The country has so far been spared widespread blackouts amid the heat wave, which heightened demand for electricity and put pressure on the grid’s infrastructure. Experts say that’s a promising sign that the grid will be able to handle intense heat waves later in the summer.

But the difficulties faced by the Michigan residents demonstrate the risks of power outages that coincide with heat waves — regardless of whether the outages are caused directly by the heat.

To help mitigate those risks, DTE Energy is planning to invest about $9 billion over the next five years to “harden” the grid to weather the effects of climate change, said Brian Calka, vice president of the company’s distribution operations business unit.

“The weather patterns that we’re seeing right now are fundamentally different from what we’ve seen in recent memory,” he said. “It’s a call to action.”

Sophia Lada contributed reporting.

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In the Mid-Atlantic and Ohio Valley, some residents are undeterred by the heat.

Preparations were made for the heat, such as bringing in city buses to serve as mobile cooling shelters, according to the show director. But 109 attendees were treated for heat-related ailments, and 12 were transported off grounds.

Some 400 miles away, in Baltimore, thousands of locals at the AFRAM Music Festival — one of the largest of its kind on the East Coast — came to celebrate African American culture. They carried tents and backpacks filled with bottled water to guard against the sun and rising temperatures.

Baltimore was even more sweltering, with a temperature of 101 and a heat index of 106 on Saturday afternoon. But still, organizers of the festival — which features activities like African drumming, mask making and music entertainment by Busta Rhymes and Big Daddy Kane, among others — were expecting some 300,000 people to attend over the weekend.

Aja Wilkinson, 24, a recent graduate of Morgan State University, was at the festival for the first time. “Even though it’s so hot, I wanted to be here for the community of it all,” she said while hopping on a cooling bus.

In Philadelphia, where the heat index shot up to 105, a group of five bicyclists were determined to go on a 60-mile ride from Valley Forge, Pa., which took about five hours. The riders, aged 52 to 69, dismissed any concerns that they might be crazy to ride in the heat.

“We’ve done 100 miles in this kind of weather,” said John Ditterle, 62. “It’s much worse in the cold.”

Still, some were struggling to cope with the unusually early heat wave. Temperatures in Philadelphia, for instance, don’t usually reach the 90s until mid-July or August, according to Derrick Fleming, a 53-year-old chef.

“It’s too sudden,” he said.

— Kevin Williams,Donna M. Owens and Jon Hurdle Kevin Williams reported from Dayton, Ohio, Donna M. Owens from Baltimore, and Jon Hurdle from Philadelphia.

The concrete jungle helps the sizzling heat feel even hotter.

When the National Weather Service releases heat index predictions, which factor humidity with temperature readings, it takes into account the urban heat island component, said Dominic Ramunni, a meteorologist at the weather service. “The value is baked into our computer model,” he said.

“Baked” is the operative word this weekend for those in New York and Newark, who are looking at a heat index of right around 100 through Sunday.

But there is a way for cities to mitigate against the heat: By incorporating more green spaces into our urban landscapes, said Amy Chester, the managing director of Rebuild by Design, a resiliency nonprofit.

“All the ways we make our cities beautiful also have the added benefit of cooling our air during heat waves, cleaning our air, absorbing rainwater to reduce flooding, raising the value of our homes and providing better health and mental health outcomes,” she said.

Trees provide shade, which lowers ambient temperatures, while green roofs, like the 6.75-acre one atop the Javits Center in Midtown, or the green terraces of Via Verde, an affordable housing development in the South Bronx, lower indoor temperatures, Ms. Chester said.

A glance at a heat map posted by the United States Geological Survey shows that temperatures in Central Park, for example, can be roughly five degrees cooler than more developed areas.

Case in point: Friday’s temperature in Central Park, a monitoring site for the National Weather Service, reached 94 degrees. At La Guardia Airport, another site with plenty of concrete and hardly any green, the high temperature was 97 degrees.

Temperatures in the city will hover in the 90s into the weekend, though potential rain could provide some relief. The Metropolitan Transportation Authority, which operates the city’s subway and buses, announced Friday that it would be on the lookout through the weekend for possible service disruptions linked to the heat.

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A ride in a chemical-sniffing van shows how heat amps up pollution.

“If you want a chemical reaction to go faster, you add heat,” said Peter DeCarlo, an atmospheric air pollution researcher at Johns Hopkins University who’s leading an effort to use the vans to measure emissions along Louisiana’s petrochemicals corridor. “On hotter days, it’s the same idea,” he said.

Air pollution surges when temperatures rise, adding to the harms wrought by global warming. It’s one reason cities and counties across the Eastern United States hit by a heat wave this week have been issuing air pollution alerts.

The past three days, New York City has warned that ozone in the city is at levels “unhealthy for sensitive groups.” Detroit and Chicago have also issued air quality alerts this week. Drivers in Ohio, Michigan, Kentucky and Indiana have been urged to avoid refueling before 8 p.m., and to car pool or refrain from driving as much as possible, to cut down on fumes.

The bad air has to do with atmospheric chemistry, Prof. DeCarlo said, while his van navigated the South Bronx, East Harlem and Midtown with two New York Times journalists along for the ride. Pollution from burning fossil fuels reacts with heat and sunlight, forming ground-level ozone. Higher temperatures turbocharge that process.

Formaldehyde emissions, which can come from sources as diverse as wildfires and household products, also rise with higher temperatures. “The same chemistry that generates high levels of ozone also produces additional hazardous air pollutants, such as formaldehyde,” Prof. DeCarlo said.

Local hot spots can sometimes be seen. For instance, on some blocks in Manhattan, formaldehyde levels were double the surrounding areas, possibly from particularly dirty combustion caused by faulty equipment nearby.

The heat-pollution nexus is a growing concern worldwide. Health harms from extreme heat aren’t the only outcome of record-breaking temperatures. Air pollution also spikes when the temperatures rise, the World Meteorological Organization said in a report last year.

“Climate change and air quality cannot be treated separately,” Petteri Taalas, the weather organization’s secretary-general, said at the time. “They go hand in hand and must be tackled together to break this vicious cycle.”

Breathing elevated levels of formaldehyde and ozone has been linked to problems like respiratory irritation and inflammation, reduced lung function, and difficulties preventing and controlling asthma attacks. Exposure is particularly concerning in people with lung diseases like asthma or chronic bronchitis, said Keeve Nachman, an environmental-health and risk-assessment researcher at Johns Hopkins and a co-lead on the mobile monitoring effort.

By coincidence this week, as New York was getting struck by the heat wave, the research team had its pollution-sniffing vans in the city to demonstrate their technology.

Prof. Nachman said that while formaldehyde was carcinogenic to humans, cancers would be expected primarily from longer-term exposures, not from temporary increases.

It’s also important to recognize that chemical exposures don’t happen one at a time, and that we’re constantly exposed to groups of chemicals that may act together to harm our health, he said. “Hot days can create situations where people are breathing many harmful chemicals at the same time,” Prof. Nachman said. “Formaldehyde and ozone are perfect examples.”

One of the vans is set to return to Louisiana later this year to measure for as many as 45 pollutants from its petrochemicals industry, part of a project funded by Bloomberg Philanthropies’ Beyond Petrochemicals Campaign. In an initial peer-reviewed study published this month, the researchers found far higher emissions of ethylene oxide, a carcinogenic gas used in plastic production, than previously known.

Researchers piloting the van, a high-tech lab-on-wheels built by the environmental measurement tech company Aerodyne, can see pollution levels in real time, and even follow plumes to try to determine their source. “It’s a bit like a video game,” Prof. DeCarlo said. “And we’re able to measure everything all at once.”

Blacki Migliozzi contributed reporting.

A short guide to understanding heat domes.

A heat dome is a high pressure system way up in the atmosphere that helps create and encase heat, kind of like a lid on a pot that holds in steam.

Heat domes “on the order of 1,000 miles across” can form under high pressure weather systems, said Hosmay Lopez, an oceanographer and expert on extreme heat and climate change with the National Oceanic and Atmospheric Administration. They become anchored in place, building up heat, sometimes for weeks at a time.

The term “heat wave” describes a rise in temperature in the weather pattern, and the term “heat dome” refers to a high pressure system that traps heat. The terms are often used interchangeably.

How do heat domes form?

When a high pressure system moves into an area, it pushes warm air toward the ground. With the sinking air acting like a cap, the warm air can’t easily escape, and it continues to heat up the more it is compressed.

“You can actually repeat this process on a small scale,” said Greg Carbin, forecast operations chief at the National Weather Service’s Weather Prediction Center. “When you’re inflating a flat tire, as the air goes in and the pressure builds, the molecules move faster, they are closer together, and they heat up.”

This high atmospheric pressure is linked to the configuration of the jet streams, bands of speedy winds that form high in the atmosphere in areas where cold air and hot air meet. The jet streams tend to be narrow, wavy corridors of air that move west to east and migrate north to south. Sometimes jet streams can expand, becoming slower, or even stagnant, and heavier.

Can heat domes happen anywhere?

Yes, they can, but areas that are farther from water, have flatter topography and are south of where jet streams migrate in the summer are more prone to oppressive heat domes. In the United States, that area is the Central Plains.

The heat domes that have covered the Pacific Northwest in recent years still baffle meteorologists, Mr. Carbin said, because the mountainous topography of the region is the opposite of what is usually conducive to heat domes.

Heat domes are associated with climate change. In the 1970s, there was one heat wave for every cold wave. As climate change accelerates, “that ratio is more than two to one, and for some places, it’s three to one,” Dr. Lopez said.

Are heat domes dangerous?

Yes. Heat stress is the most common cause of weather-related deaths, according to the World Health Organization. Because heat domes are associated with stagnating air, they can also lead to reduced air quality, dryness and a greater chance of fire. “Those stains are very detrimental for human health, especially for the elderly and people with preconditions like cardiopulmonary illnesses,” Dr. Lopez said.

Read about staying safe in a heat wave here.