Three fastest-warming cities in the U.S. are in the Mountain West

Since 1970, summer temperatures in Reno, Nevada, have risen 10.9 degrees, making it the nation’s fastest-warming city, according to Climate Central, a nonprofit research group.

Ranked second is Las Vegas, Nevada, which has seen an increase of 5.8 degrees. Boise, Idaho, follows in third at 5.6 degrees.

Stephanie McAfee, Nevada state climatologist, says a contributing factor to the warming is urban growth. Those three Mountain West cities, she explains, are expanding quickly, turning undeveloped land into new homes and roads.

“A light-colored bit of ground, sand or concrete or something is going to be cooler than a black asphalt roadway,” McAfee said. “As we have darker colored materials in the city, they can absorb more heat.”

And those materials release the heat at night, causing warmer-than-usual overnight temperatures. In Reno, the nighttime summer temps have jumped from the upper 40s and low 50s to the high 50s and mid-60s, according to McAfee.

This phenomenon is known as the “heat island effect.”

As a result, she says, air conditioning is becoming a bigger part of people’s budgets. That’s at a time when U.S. consumers are dealing with the highest inflation in 40 years.

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, the O’Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.

The photo included in this story is licensed under Flickr Creative Commons.