Go Back
  • For Business
  • |
  • Warnings
  • Data Suite
  • Forensics
  • Advertising
  • Superior Accuracy™
Flood-weary Texas finally drying out, but near 100-degree heat looms Chevron right
Tropical rainstorm soaks Florida, could strengthen in Gulf before targeting Louisiana Chevron right

Columbus, OH

88°F
Location Chevron down
Location News Videos
Use Current Location
Recent

Columbus

Ohio

88°
No results found.
Try searching for a city, zip code or point of interest.
settings
Columbus, OH Weather
Today WinterCast Local {stormName} Tracker Hourly Daily Radar MinuteCast Monthly Air Quality Health & Activities

Around the Globe

Hurricane Tracker

Severe Weather

Radar & Maps

News

News & Features

Astronomy

Business

Climate

Health

Recreation

Sports

Travel

For Business

Warnings

Data Suite

Forensics

Advertising

Superior Accuracy™

Video

Winter Center

AccuWeather Early Hurricane Center Top Stories Trending Today Astronomy Heat Climate Health Recreation In Memoriam Case Studies Blogs & Webinars

News / Weather News

Why nighttime heat can be so dangerous and why it’s getting worse

On average, nights are warming faster than days in most of the United States, a national climate assessment found.

By Rachel Ramirez, CNN

Published Jun 30, 2023 5:13 PM EDT | Updated Jun 30, 2023 5:13 PM EDT

Copied

Do you know the signs of heat exhaustion? What about where to find a cooling shelter if you have no power or shelter from the heat? Here’s a rundown of what you should know.

(CNN) — Summers are getting hotter than ever, shattering all-time high temperature records, straining the energy grid and damaging critical infrastructure.

Heat waves also are coming to include another increasingly dangerous element: overnight temperatures that don’t cool down enough to offer sufficient reprieve from stifling heat, particularly for people without access to air conditioning.

“Most people don’t realize that hot nighttime temperatures have been outpacing daytime temperature increases across most populated regions worldwide in recent decades,” Columbia University’s Data Science Institute postdoctoral research scientist Kelton Minor told CNN.

Brian Jones runs sprints up Capitol Hill as he works out in the heat, Friday, June 30, 2023 in Nashville, Tennessee. (AP Photo/George Walker IV)

Hotter nights are a consequence of the climate crisis, scientists have warned. On average, nights are warming faster than days in most of the United States, the 2018 National Climate Assessment found.

“We think it’s because as the days grow warmer, there is more moisture in the air that traps the heat,” the Medical Society Consortium on Climate and Health’s executive director, Lisa Patel, told CNN. “During the day, that moisture reflects the heat, but at night, it traps the heat in.”

Increasing nighttime heat is even more common in cities because of the urban heat island effect, in which metro areas are significantly hotter than their surroundings.

Places with a lot of asphalt, concrete, buildings and freeways absorb more of the sun’s heat than areas with ample parks, rivers and tree-lined streets. At night, when temperatures are supposed to cool down, the retained heat is released back into the air, said University of Washington climate and health expert Kristie Ebi.

Areas with a lot of green space – with grass and trees that reflect sunlight and create shade – are cooler on summer’s hottest days, she said.

“Many cities put together cooling shelters, but people have to know where they are, how to get to them and what hours they operate,” Ebi told CNN, noting city officials must rethink urban planning to consider climate change.

“It’s going to take a while for trees to grow, but we need tree-planting programs focusing on places that are particularly vulnerable, making sure that city planning takes into account that we’re heading into a much warmer future.”

Nighttime should be when our bodies get a break from the heat, Patel said. But with the climate crisis, it’s becoming less likely to happen. Heat-related deaths could increase sixfold by the end of the century due to warmer nighttime temperatures, unless planet-warming pollution is significantly curbed, a 2022 study in the Lancet Planetary Health found.

Andres Matamoros wipes the sweat from his face while selling fresh fruit and cold coconuts from his roadside stand Wednesday, June 28, 2023, in Houston. Meteorologists say scorching temperatures brought on by a heat dome have taxed the Texas power grid and threaten to bring record highs to the state. (AP Photo/David J. Phillip)

The climate crisis is already affecting people’s ability to sleep, said Minor, co-author of a study that found people living in warmer climates lose more sleep for each degree of temperature increase. It was published in May in the journal One Earth.

“We all know what it’s like to try to fall asleep on a hot night – it’s uncomfortable,” Patel said. “We often lose sleep. It is estimated that by the end of the century, we could lose about two days of sleep per year, and it will be worse for people without access to air conditioning.”

At its most extreme, when a human body does not get the chance to recover – typically at night – heat stress can progress to heat stroke, which is associated with confusion, dizziness and passing out, Patel explained.

People around the world are already losing roughly 44 hours of sleep every year on average due to warm nighttime temperatures during just the first part of the 21st century, Minor’s study estimated. He calls this “sleep erosion,” noting each person may lose up to 58 hours of sleep by the end of the century.

“People in our study did not appear to make up for lost sleep on hotter nights by napping during the day or by sleeping more during the days or weeks after,” Minor said. “In fact, they lost additional sleep over these periods due to a delayed temperature effect, possibly due to ambient heat being trapped indoors.”

Issac Bowman rides his bike on dirt trails in Austin, Texas, Wednesday, June 28, 2023. (AP Photo/Eric Gay)

And much like other social issues, the impacts don’t fall equally across communities, he said.

“For every degree of nighttime temperature rise, we found that the elderly lost over twice as much sleep as middle-aged adults, females lost slightly more sleep than males, and critically, residents of lower-middle-income countries lost three times as much sleep compared to people living in higher income countries,” Minor said.

Heat waves that go on for several days tend to be associated with more deaths as the body can no longer keep itself cool, Patel said.

And unless planet-warming pollution is curbed, the climate crisis is set to increase exposure to dangerous heat index levels by 50% to 100% in much of the tropics and by up to 10 times across much of the globe, according to a 2022 study published in Communications Earth & Environment.

“Living through a heat wave during the day can be like running a race,” Patel said. “We need a cool break to recover and recuperate, and when nighttime temperatures don’t drop, we don’t get that critical time we need to relieve the stress on our bodies from being overheated during the day.”

The-CNN-Wire™ & © 2023 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.

SEE ALSO:

Hundreds of dolphins, sea lions are washing up dead or sick in Calif.
Extreme temperatures have killed at least 112 in Mexico since March
Las Vegas breaks longstanding temperature record
Extreme heat to shift from Texas to Southeast
Report a Typo

Weather News

Weather News

Death toll reaches 129 in Texas as new flash flood threat expands

Jul. 13, 2025
Weather Forecasts

Flood-weary Texas finally drying out, but near 100-degree heat looms

Jul. 14, 2025
Weather News

The Deadliest Floods in Texas History: A State at Risk

Jul. 14, 2025
video

Before-and-after pictures show devastation caused by Texas floods

Jul. 9, 2025
Severe Weather

Severe weather to rumble in the central US through the holiday weekend

Jul. 6, 2025
Weather News

Record sargassum seaweed piles up on Caribbean islands, Gulf

Jul. 2, 2025
Weather News

Alabama teen in ICU after lightning strike hits boat, causing burns an...

Jul. 2, 2025
Show more Show less Chevron down

Topics

AccuWeather Early

Hurricane Center

Top Stories

Trending Today

Astronomy

Heat

Climate

Health

Recreation

In Memoriam

Case Studies

Blogs & Webinars

Top Stories

Weather Forecasts

Flood-weary Texas finally drying out, but near 100-degree heat looms

3 minutes ago

Weather News

Thunderstorms bring more flooding, evacuations to central Texas

1 hour ago

Hurricane

Tropical trouble in the Atlantic may brew this week

4 hours ago

Weather News

Grand Canyon fires force closures

1 hour ago

Severe Weather

Wildfire smoke may follow storms, severe weather in eastern US

23 minutes ago

More Stories

Featured Stories

Recreation

Yellowstone’s landscape shifts again with discovery of new hot pool

3 hours ago

Weather News

Orcas are bringing humans gifts of food – but why?

3 days ago

Health

How can families handle new anxieties around summer camp?

3 days ago

Business

Samsung is looking into more AI devices potentially including earrings...

3 days ago

Weather News

The US has a plan to breed millions of flies and drop them from planes

4 days ago

AccuWeather Weather News Why nighttime heat can be so dangerous and why it’s getting worse
Company
Proven Superior Accuracy About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™ Personal Weather Stations
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
Company
Proven Superior Accuracy About AccuWeather Digital Advertising Careers Press Contact Us
Products & Services
For Business For Partners For Advertising AccuWeather APIs AccuWeather Connect RealFeel® and RealFeel Shade™ Personal Weather Stations
Apps & Downloads
iPhone App Android App See all Apps & Downloads
Subscription Services
AccuWeather Premium AccuWeather Professional
More
AccuWeather Ready Business Health Hurricane Leisure and Recreation Severe Weather Space and Astronomy Sports Travel Weather News Winter Center
© 2025 AccuWeather, Inc. "AccuWeather" and sun design are registered trademarks of AccuWeather, Inc. All Rights Reserved.
Terms of Use | Privacy Policy | Cookie Policy | About Your Privacy Do Not Sell or Share My Personal Information

...

...

...