Nights are warming faster than days in the U.S.
Nights on average are heating up faster than days in most parts of the United States — a trend caused by climate change, according to the 2018 National Climate Assessment Report, newly cited by the New York Times.
Why it matters: Last month was the hottest June on record for the U.S., and more than 1,500 areas of the country logged new record-high overnight temperatures toward the end of the month.
Abnormally high nighttime temperatures can increase the risk of heat-related hospitalizations and deaths because prolonged stretches of hot weather prevent people from cooling off from the day’s heat.
- They can also worsen wildfire conditions because fires typically die down overnight when temperatures dip, the air cools and humidity increases.
What they're saying: “[I]t’s really important that people have an opportunity to bring their core body temperature down,” Kristie Ebi, an environmental health scientist at the University of Washington, told the Times.
- “When it’s really hot at night, you don’t have that relief and it puts more physiological strain on your body," Ebi added.
How it works: Meteorologists and other scientists believe nights are heating up as temperatures rise throughout the day and the air is able to hold more moisture.
- They theorize that the increased moisture in the air traps heat close to the ground’s surface, producing warmth that can persist throughout the night.
Go deeper: Pacific Northwest heat wave "virtually impossible" without climate change