Record Humidity Levels Impact Eastern U.S. Amid Climate Change
Over 70 million Americans east of the Rockies experienced unprecedented humidity during June and July 2025, with climate change contributing to rising dew points and oppressive conditions.
During June and July 2025, more than 70 million Americans east of the Rocky Mountains experienced the most humid start to summer on record, according to an Associated Press analysis of data from the Copernicus Climate Service. The average daily dew point—a key measure of humidity—reached 66 degrees Fahrenheit, surpassing all previous records since measurements began in 1950.
Cities such as Philadelphia, Washington, and Baltimore recorded an unprecedented number of days with dew points exceeding 75 degrees, levels considered oppressive even by tropical standards. This high humidity led to dangerously warm nights, with several cities breaking or nearing records for highest overnight lows. Zack Taylor, forecast operations chief at the National Weather Service’s Weather Prediction Center, noted that elevated nighttime temperatures hinder the body's ability to cool and recover from daytime heat.
Climate experts attribute this trend to climate change, with the Eastern U.S. experiencing a 2.5-degree increase in summer dew points since 1950. Cameron Lee, a climate scientist at Kent State University, observed that regions are not only facing higher average humidity but also more extreme humid days, with super sticky conditions now occurring more frequently and over larger areas. Marshall Shepherd, a meteorology professor at the University of Georgia, remarked that summers today are markedly different from those experienced by previous generations.