Data analysis by the Associated Press shows that 70 million Americans sweat during the first two months of summer due to climate change records, as climate change significantly dials the humidity in the eastern U.S. in recent decades.
This means that many cities have spent uncomfortable warmth and potentially dangerous nights in many cities over the past few weeks, the National Weather Service said.
27 states and part of Washington, D.C. have recorded days, which meteorologists call uncomfortable-average daily Dew points According to Copernicus Climate Services, 65 degrees Fahrenheit in June and July.
That’s just the average every day. In much of the East, trouble keeps rising to tropical levels, lasting for several hours. Philadelphia has 29 days, Washington has 27 days, Baltimore has 24 days of dew to reach at least 75 degrees, and even Tampa’s Meteorological Services offices call oppressiveness.
Dew point is a measure of moisture in the air expressed in degree, which many meteorologists call the most accurate method to describe humidity. AP calculations show that the dew point in summer 2025 has been at least 6 degrees higher than normal in 1951-2020 in Washington, Baltimore, Pittsburgh, Richmond, Columbus and St. Louis. The average June and July humidity across the country east of the Rocky Mountains rose above 66 degrees, higher than any year since measurements began in 1950.
“It’s a very stuffy summer. The humid heat has risen,” said Bernadette Woods Placky, chief meteorologist at the Climate Center.
Cameron Lee’s Cameron Lee, a climate scientist and humidity expert twice this summer, had a dew point of about 82 degrees at his home weather station in Ohio. That’s it Various charts used by meteorological services Describe the feeling of dew point.
“Some parts of the United States have not only experienced greater average humidity, especially in spring and summer, but also in more extreme wet days,” Lee said. He said the super sticky days are now extending more days and more land.
High humidity doesn’t allow air to cool as usual at night, and stickiness contributes to multiple nighttime temperature records in the Ohio Valley until the mid-Atlantic and upper and lower coastal states, said Zack Taylor, head of forecasts for National Weather Services. Raleigh, Charlotte, Nashville, Virginia Beach, Virginia and Wilmington, North Carolina, all hit record hottest overnight lows. He said New York City, Columbus, Atlanta, Richmond, Knoxville, Tennessee and Concord, New Hampshire are close.
“What really affects the body is the night temperature,” Taylor said. “So if there is no cooling at night, or if there is no cooling, it won’t let your body cool and recover from a potentially very hot afternoon. So when you start seeing it for a few days, it does wear down the body, especially of course, if you can’t get into the cooling center or the air conditioner.”
one Extra heat and Rain summer Woods Placky said weather patterns are combined with climate change that burns coal, oil and gas.
AP analysis of Copernicus data showed that areas east of the Rocky Mountains averaged about 2.5 degrees at summer dew point. In the 1950s, 1960s, 1970s, 1980s and 1990s, the average dew point in the eastern part of the country was low in the 1960s, and the weather service said was striking, but OK. In four of the past six years, this number has approached even a discomfort line of 65.
“It’s big,” Lee said of the 75-year trend. “This suggests a significant increase in a relatively short period of time.”
This increase in average dew point at average dew point does mean the worst super nausea days that happened once a year in the past, and now it happens a few times a summer, which affects people, Lee said.
Higher humidity and calories feed each other. Meteorologists say the basic law of physics is that the atmosphere is 4% more than each degree of Fahrenheit (7% Celsius per degree).
Taylor said the Midwest and East were trapped in incredible thermal high-pressure systems throughout most of the summer, which would increase temperatures or have higher than average rainfall. What is mainly missing is the occasional cool front, which pushes out the most pressing heat and humidity. This finally caused relief in August, he said.
Humidity varies with the region. The West is drier. In summer, dew in the south has a dew point of 65 degrees than in the north. But that is changing.
Marshall Shepherd, a professor of meteorology at the University of Georgia, said uncomfortable humidity is moving northwards into places people are not used to.
“It’s not your grandparents’ summer,” he said.
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Borenstein reported from Washington and Wildeman, Hartford, Connecticut.
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