It’s the humidity that gets you. Here’s why — and tips for dealing with muggy days

VPM | By Michel Martin and Kaity Kline

Published June 20, 2025 at 9:00 AM EDT

Large swaths of the U.S. will experience intense heat and humidity in the coming days.

Updated June 20, 2025 at 15:28 PM ET

It’s not the heat that gets you — it’s the humidity.

Millions will feel that firsthand over the coming days as a heat dome is expected to bring extreme heat and humidity for much of the U.S.

Those humid conditions will make temperatures feel even hotter and pose health risks to many.

Why is that?

In an interview with Morning Edition, Sheetal Rao, an internal medicine physician at UI Health — the academic health enterprise of the University of Illinois Chicago — with a focus on how the environment affects health, explained that high levels of humidity simply make it feel hotter and challenge our body’s mechanisms to regulate temperature.

Here’s what she had to say about humidity and how to stay cool:

Why humidity poses risks during extreme heat

One of the human body’s main ways of cooling down is sweating, and that sweat evaporating off the body. When it’s humid, sometimes that isn’t enough, Rao said.

“When the air is so full of moisture, that evaporation doesn’t happen as efficiently or effectively, and so we aren’t able to cool down as well,” Rao said.

Rao said high humidity poses the strongest risk to seniors and young children, as well as pregnant women.

But it can also come down to the exertion level of outdoor activity.

“So even a regular, healthy person who is out working very hard in the heat and humidity would be vulnerable,” Rao said. “And then, of course, people who are outdoors more for their job or people who are unhoused and then certain medications as well can make people more vulnerable.”

How can you stay safe during humid days?

While some people may initially feel that sitting by a fan alleviates the worst of the heat, Rao said that might not be enough on humid days. That’s because the sweat on one’s body doesn’t have any place to evaporate off the skin because the air is already so full of water vapor.

“The fan kind of just cycles the same air around and it won’t effectively cool people when it’s very hot and humid,” Rao added.

If you don’t have air conditioning, Rao recommends getting some rest, taking regular breaks, closing blinds to cool down your home, hydrating and wearing loose-fitting clothes.

“But at some point when it gets very hot, air conditioning is likely the only intervention that’s going to help you feel cool,” Rao said. “And so there are places that people can go to get cool, like cooling centers, but also just public buildings like libraries and malls and things like that.”

The digital version of this story was adapted for the web by Obed Manuel and edited by Suzanne Nuyen.

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Michel Martin

Michel Martin is the weekend host of All Things Considered and host of the Consider This Saturday podcast, where she draws on her deep reporting and interviewing experience to dig in to the week's news. Outside the studio, she has also hosted "Michel Martin: Going There," an ambitious live event series in collaboration with Member Stations.

Martin came to NPR in 2006 and launched Tell Me More, a one-hour daily NPR news and talk show that aired on NPR stations nationwide from 2007-2014 and dipped into thousands of important conversations taking place in the corridors of power, but also in houses of worship, and barber shops and beauty shops, at PTA meetings, town halls, and at the kitchen table.

She has spent more than 25 years as a journalist — first in print with major newspapers and then in television. Tell Me More marked her debut as a full-time public radio show host. Martin says, "What makes public radio special is that it's got both intimacy and reach all at once. For the cost of a phone call, I can take you around the world. But I'm right there with you in your car, in your living room or kitchen or office, in your iPod. Radio itself is an incredible tool and when you combine that with the global resources of NPR plus the commitment to quality, responsibility and civility, it's an unbeatable combination."

Martin has also served as contributor and substitute host for NPR newsmagazines and talk shows, including Talk of the Nation and News & Notes.

Martin joined NPR from ABC News, where she worked since 1992. She served as correspondent for Nightline from 1996 to 2006, reporting on such subjects as the congressional budget battles, the U.S. embassy bombings in Africa, racial profiling and the aftermath of Hurricane Katrina. At ABC, she also contributed to numerous programs and specials, including the network's award-winning coverage of Sept. 11, a documentary on the Anita Hill-Clarence Thomas controversy, a critically acclaimed AIDS special and reports for the ongoing series "America in Black and White." Martin reported for the ABC newsmagazine Day One, winning an Emmy for her coverage of the international campaign to ban the use of landmines, and was a regular panelist on This Week with George Stephanopoulos. She also hosted the 13-episode series Life 360, an innovative program partnership between Oregon Public Broadcasting and Nightline incorporating documentary film, performance and personal narrative; it aired on public television stations across the country.

Before joining ABC, Martin covered state and local politics for the Washington Post and national politics and policy at the Wall Street Journal, where she was White House correspondent. She has also been a regular panelist on the PBS series Washington Week and a contributor to NOW with Bill Moyers.

Martin has been honored by numerous organizations, including the Candace Award for Communications from The National Coalition of 100 Black Women, the Joan Barone Award for Excellence in Washington-based National Affairs/Public Policy Broadcasting from the Radio and Television Correspondents' Association and a 2002 Silver Gavel Award, given by the American Bar Association. Along with her Emmy award, she received three additional Emmy nominations, including one with WNYC's Robert Krulwich, at the time an ABC contributor as well, for an ABC News program examining children's racial attitudes. In 2019, Martin was elected into the American Academy of Arts and Sciences for outstanding achievement in journalism. She is the 2021 recipient of PMJA's 2021 Leo C. Lee Award.

A native of Brooklyn, N.Y., Martin graduated cum laude from Radcliffe College at Harvard University in 1980 and earned a Master of Arts from the Wesley Theological Seminary in 2016.

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