Record muggy heat hits the eastern United States

An AP data analysis shows record humidity across the eastern United States this summer driven by climate change.

Record muggy heat hits the eastern United States

More than 70 million Americans have endured the muggiest start to summer on record as dew points persist above 65 degrees in large swaths of the eastern United States. In June and July, 27 states and Washington, D.C., logged record days with uncomfortable humidity, according to an Associated Press analysis of Copernicus Climate Service data. City-level tallies show Philadelphia with 29 days of dew points at or above 75 degrees, while Washington had 27 and Baltimore 24. Meteorologists note this is not just a higher daytime heat wave but a sustained stretch of sticky nights, which keeps overnight temperatures elevated and slows cooling.

Experts say the trend reflects a long-running shift linked to climate change from burning coal, oil, and gas. The eastern region now averages dew points around 66 degrees for June and July, higher than any year since measurements began in 1950. A number of days have dew points in the 70s, and scientists say the sticky pattern is spreading north. The pattern has been reinforced by persistent high pressure and unusually wet weather, with August bringing some relief but not a full end to the muggy days.

These humidity increases change everyday life. High humidity means more energy use for cooling, stressed power grids, and sleep disruption for people in crowded housing or without air conditioning. Health officials warn that long nights of heat can aggravate heart and lung conditions, especially for the elderly and children. The trend also challenges public infrastructure, from schools to transit systems, that were not designed for this level of moisture and heat. The data shows a clear signal: climate change is rewriting the map of comfortable seasons in the United States and demanding new kinds of adaptation.

Highlights

Communities will need proactive heat plans and resilient energy networks.