“Hot,” said Phillips, 49, sweating as she walked from the community center to her home at the Highland Dwellings public housing development. “It’s all the same to me. . . . Hot, period.”

But researchers increasingly are learning that the way a city’s climate functions is significantly more complicated than what Phillips and many others believe — that regardless of socioeconomic status and race, we all bake the same.

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The reality is, we don’t.

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As Washington sweats through yet another wave of oppressively hot days, heat has become one more way to measure inequality in a city already defined by it. Like educational attainment, wealth accumulation and life expectancy, where you live is a deciding factor. Your location in the city not only dictates how hot it is, but also the likelihood that the heat itself will be dangerous: The poor, who often cannot afford air conditioning and are more likely to have medical conditions that are exacerbated by heat, have fewer ways to escape it.

“Some people have a much hotter day than others,” said Jeremy S. Hoffman, a climate and earth scientist working with the National Oceanic and Atmospheric Administration to map the heat in Baltimore and Washington. If the results, expected to be finished sometime this month, bolster earlier research in Washington and echo studies in other heavily populated urban areas, it will show that wealthier neighborhoods, which often have a lot of trees, yards and parks, will be cooler than poorer neighborhoods, which often don’t.

The studies come at a time when cities like Washington are beginning to grapple with the prospect of an increasingly hot future, the result of climate change and the unforeseen consequences of urban development. In the same way sprawl has left some cities vulnerable to crippling floods, it has also created vast, industrialized “heat islands” — urban places without much vegetation, but blocks of impervious surfaces such as asphalt and concrete that absorb heat all day then release it slowly into the night, causing temperatures to spike then as well.

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This effect is stronger in Washington than in just about any other city, according to a 2014 report by Climate Central, which found that the city is the country’s sixth most intense urban heat island. Summer is nearly 5 degrees warmer in Washington than in the surrounding area, and warmer still during the night, when the temperature is on average 7.1 degrees higher.

But wide variances in temperatures also apply within the city’s boundaries.

“Land cover can be so different, and the amount of concrete varies so greatly, that it can be 65 someplace [in the city] and 75 in another place,” said Yesim Sayin Taylor, executive director of the D.C. Policy Center. “Wards 2 and 3 have lots of trees and parks, and there, the heat has a way of escaping. . . . But there are other parts of the city that are equally [residential], but because they don’t have the tree coverage, they experience higher heat.”

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Nearly 40 percent of Washington residents in low-income communities live in areas with fewer trees and more empty space, according to data on the region’s tree canopy compiled by the University of Vermont’s Spatial Analysis Laboratory and analyzed in 2013 by The Washington Post. The analysis found that 80 percent of residents in upper-income areas lived in neighborhoods with a robust tree canopy.

Last year, the D.C. Policy Center published a report that added more detail to how heat affects Washington residents. It overlaid temperature with social, economic and health-related factors, as well as vegetation variability, to yield what it called a heat vulnerability index.

People who live in poorer, historically African American communities in Northeast and Southeast Washington, where many residents rent and have less ability to landscape or plant trees, are more at risk of heat-related illnesses than the people in more well-off communities, the report found.

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The ones most at risk: Buzzard Point, Edgewood and Washington Highlands, one of the city’s poorest neighborhoods and where residents of Highland Dwellings say they’re enjoying just about everything about a recent redevelopment of the public housing complex — except for the loss of large trees. In their place are freshly planted adolescent trees, granting shade to exactly no one.

“All the trees are gone now,” said one man who declined to give his name, sitting in the sun at 2 one recent afternoon among a group of friends. “And it’s way hotter now.”

In the shade of her porch, one block down, sat Cheryl Johnson, 63. She shook her head and reached for her walker. “It’s so hot out here,” said Johnson, who receives Supplemental Security Income and is particularly vulnerable to the heat because she is on kidney dialysis.

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“Ward 8 is the worst ward there is. . . . Ain’t no movie theaters, no parks — no nothing” to provide relief from the sweltering weather, said her friend, Diane Jones.

Johnson’s doctor tells her to stay inside, but she said she was getting cabin fever at her air-conditioned apartment and decided to venture out to socialize and give her Rottweiler, Diesel, some fresh air.

She knows that she could come to regret spending time outside on summer days. “I don’t want to die,” she said.

But for today at least, she sat and felt at peace, looking at the places where big trees once stood, Diesel at her side, as the day slowly baked away.

Dig Deeper: Environment + U.S. Cities

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Want to explore how climate change is affecting cities across America? Check out our curated list of stories below.

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California is hotter and drier than ever before because of climate change. The result: More, bigger and faster wildfires that leave little time for evacuation and cost billions to fight and recover from.

The Jefferson Memorial in Washington sits on a landfill and it’s sinking. Some walkways flood twice a day.