Record-Breaking Heat Dome Engulfs U.S., No Relief During Hot Nights

Heatwave Intensifies as U.S. Faces Unprecedented High Temperatures

The United States is currently experiencing an intense heatwave, with temperatures soaring to potentially record-breaking levels. A heat dome has enveloped regions from the Midwest to the Atlantic Coast, causing not only sweltering daytime conditions but also unusually warm nights. This combination elevates the risk for heat-related illnesses, especially for those lacking air conditioning.

“We’re seeing temperatures well into the evening that are staying shockingly high and, in some cases, never dropping below 80 or 75 degrees. And this is really concerning,” stated Ashley Ward, director of the Heat Policy Innovation Hub at Duke University’s Nicholas Institute. Ward attributes these conditions to the worsening effects of climate change.

In the Baltimore-D.C. area and southeastern Pennsylvania, including Philadelphia, the National Weather Service forecasted Thursday highs in the low to mid-100s, with heat indices approaching 110°F. Overnight temperatures are expected to remain in the low 80s. A similar forecast is set for Friday.

Climate change has resulted in more frequent heatwaves and an increase in hot nights each summer. The Fifth National Climate Assessment notes that nighttime temperatures are rising faster than daytime temperatures across the U.S., with the exception of the Northern Great Plains. “The number of nights where the temperature never falls below 70°F is increasing everywhere in the US except the Northern Great Plains,” the report states.

Meteorologist Alex DaSilva from Accuweather explains the situation, saying, “The trends have been for those overnight lows to be warmer and warmer and warmer, especially when we’re dealing with these big heat wave events.” This shift is due to the atmosphere retaining more heat at night, which leads to higher starting temperatures during the day.

Humidity levels, intensified by climate change, further exacerbate the issue. Afternoon showers may not provide relief as expected. “It can even feel worse sometimes after a rain shower or a thunderstorm comes through,” DaSilva added.

Ward emphasized the impact of humidity, stating, “People can’t evaporate the sweat off of our skin when there’s so much water content in the air,” which can lead to heat stroke or heat exhaustion.

Kenney, speaking to NPR’s Morning Edition, explained, “It’s really a combination of temperature and relative humidity. The sweating response is really only valuable if that sweat can evaporate.”

While most U.S. households had air conditioning by 2020, according to the U.S. Energy Information Administration, a study by KFF revealed disparities. Asian, Black, and Hispanic households, as well as lower-income households, are less likely to have air conditioning compared to White and higher-income households.

Older adults are particularly vulnerable to these extreme conditions, especially those with heart disease and diabetes, Kenney noted. He advises gradual acclimatization to the heat and staying hydrated, emphasizing the importance of drinking fluids before and after heat exposure.