By Alex Fitzpatrick, Axios, June 17, 2025

Summer evenings are getting warmer across much of the U.S. — especially in Nevada and other parts of the Southwest — amid climate change, a new analysis shows.

Why it matters: Higher overnight temperatures can have health consequences for vulnerable groups, as well as increase demand for air conditioning.

That, in turn, can strain electrical grids and increase energy demand, fueling a vicious cycle with more greenhouse gas emissions.

Driving the news: Average summer nighttime temperatures increased between 1970 and 2024 in 96% of 241 locations analyzed in a new report from Climate Central, a research and communications group.

Among cities with an increase, temperatures rose by 3.1°F on average.

Zoom in: Reno, Nevada (+17.7°F), Las Vegas (+10°F), El Paso, Texas (+8.9°F) and Salt Lake City (+8.2°F) saw the biggest increases.

What they're saying: "There's a lot of work ahead of us, and we don't have all the answers," Brian Beffort, sustainability manager for Reno's Washoe County, recently told the Las Vegas Review-Journal.

"I'm focused on trees because they check the most number of boxes: They clean the air. They prevent stormwater. They cool things off ... There's a lot of planning that we need to do. But that's not the only intervention that we need."

Between the lines: Hundreds of U.S. cities are experiencing more frequent warmer-than-average summer nights "with a strong climate change fingerprint," Climate Central says.

That's based on the group's "Climate Shift Index" — a method of measuring climate change's impact on local daily temperatures — and the 1991-2020 climate normals.

The bottom line: It isn't just daytime highs getting warmer in much of the U.S., but evening lows, too.

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