Climate Scientists Warn Hotter Summer Nights Worsening Health

Climate scientists are warning that not only summer days, but summer nights are getting hotter, creating a public health worry, according to a new report.

Night temperatures are not dropping far enough in comparison to the peak highs in the 80s and 90s or more, making it harder for people to find relief, reports ABC News, quoting Climate Central, a nonprofit organization that analyzes climate science.

Heat waves are responsible for more deaths in the United States than other extreme weather events such as tornadoes, floods, or hurricanes, according to the National Weather Service.

This week alone, heat alerts have been issued across much of the United States, stretching from Florida to South Dakota and up the East Coast to Boston, affecting more than 200 million people.

The heat warnings mean that humidity and other factors drive temperatures that read in the 80s and 90s up to "feels-like" temperatures in the triple digits during the afternoon hours, and even when the sun goes down, the heat remains.

Climate Central has analyzed summer nighttime temperatures in 241 locations nationwide from 1970 to 2024 and has found that temperatures have become warmer in nearly all locations, with an average increase of 3.1 degrees Fahrenheit.

But according to the Environmental Protection Agency, warm summer nights are expected to become even more common in the upcoming decades, with a projected nighttime temperature average to remain above 70 degrees.

Meanwhile, the human body faces more strain in trying to regulate its temperature if the air stays too warm at night, notes the Centers for Disease Control and Prevention.

Without the drop in temperature, vulnerable people such as the elderly, children, and people with preexisting health conditions could be at risk for increased health issues, notes the CDC.

Warmer nights can also lead to poor sleep quality, which impairs a person's immunity, increases the risk of chronic conditions like heart disease, and worsens mental health issues, the CDC information added.

It's not only humans that can feel the effects of hot nights. Ecosystems and infrastructure need cooler nights to recover after a blistering hot day.

Cities are particularly vulnerable, with the amount of concrete and asphalt that retains heat, reports the EPA.

And when compared with rural areas, cities have higher overnight temperatures because of the lack of vegetation, which has become known as the "urban heat island" effect.