Las Vegas is one of the fastest warming cities in the United States.
Heat stroke kills more Americans each year than hurricanes, floods, tornadoes, or cold weather. When it’s hot, our hearts work hard to cool us down, pumping blood back to the surface of the skin. But when the nights are hot, our hearts have no time to rest, working in overdrive and depriving other organs of blood.
In July, Las Vegas recorded its hottest temperature ever, hitting 120 degrees. Even more astonishing, the temperature never dropped below 94 degrees for three consecutive nights.
“Everybody focuses on the high temperatures, but the overnight lows are what go unnoticed,” said Matt Woods, a meteorologist with the National Weather Service in Las Vegas.
In June and July of this year, there were only seven days in Las Vegas where the nighttime temperature was 79 degrees or higher. As the weather continues to warm, air conditioning becomes a basic necessity rather than just a luxury, especially at bedtime. And more and more people are experiencing hot nights. No major American metropolitan area has grown more than Las Vegas in the past 30 years.
Bridget Bennett, The New York Times
This growth has led to an increase in roads, cars and housing over vast areas, creating one of the most extreme urban heat island effects in the U.S. At night, heat trapped inside the asphalt and buildings is released into nearby areas, making the city 20 to 25 degrees warmer than the surrounding desert.
This trapped heat adds to the warming caused by climate change, leading to even more extreme temperatures.
“It’s like playing with rigged dice,” said Ariel Choinard, director of the Desert Institute’s Southern Nevada Heat Resistance Laboratory.
“As the planet continues to warm, we’re going to have more and more hot nights.”
According to the Southern Nevada Health Department, 294 people died from heatstroke in Clark County, which includes Las Vegas, in 2023. But a Duke University analysis of deaths nationwide estimated that the official tally is an underestimate and the real number is probably several times higher.
Go towards the heat
Las Vegas is not the only fast-growing metropolitan area experiencing an increase in unusually hot nights — nights with overnight lows at least 95 percent of the temperatures seen between 1961 and 1990.
Variations in hot nights in the six fastest-growing major metropolitan areas of the United States
Changes in the metro area
Demographic Changes
Unusually Hot Nights Las Vegas +206% Austin, TX +170% Raleigh, NC +161% Orlando, FL +118% Phoenix +117% Atlanta +98%
Source: Decennial Census, National Weather Service
Figures show the change in population of core-based statistical areas from 1990 to 2020 and the change in the number of abnormally hot nights in the city from 1961 to 1990. An abnormally hot night is one that exceeds the 95th percentile of the minimum temperature from 1961 to 1990. A metropolitan area is a metropolitan area with a population of more than 1 million in 2020.
The nation’s fastest-growing metropolitan areas — Sunbelt cities including Austin, Raleigh, Orlando, Phoenix and Atlanta — have seen substantial increases in nighttime temperatures. Their populations have more than doubled in a generation, and the number of unusually hot nights has increased at a similar rate.
The clash between these two forces has put some of these cities on a dangerous path with little relief even in the middle of the night.
An unusually hot night in…
Source: National Weather Service
Note: In some cases, weather stations may have been relocated to other locations within the city.
The Sunbelt is a magnet for older adults who move there from other parts of the country in search of sunnier days and a lower cost of living, but seniors are less tolerant of the heat and account for more than 80% of heat-related deaths, according to a Climate Central report.
More new homes are being built in the Sun Belt than anywhere else in the country, but the region hasn’t been immune to the national housing crisis: Sun Belt home prices are significantly higher than they were before the pandemic, rents are above the national average, and Las Vegas and Phoenix have some of the highest eviction rates in the country.
Some residents, already sensitive to energy bills, are having to conserve air conditioning at night when they need it most, and homelessness, which increased by 26% in Nevada and 30% in Arizona between 2020 and 2023, has few options for shelter from inclement weather at any time of the day or night.
All this means that unsustainably expanding cities are creating more vulnerable populations at a time of increasing risk.
Growing danger
“The experience of heat varies greatly from person to person,” Choinard says, “and it depends a lot on who you are, where you live, and a variety of other factors, including your socioeconomic stability.”
The city center is at a lower elevation than the surrounding area, its wide roads paved with dark asphalt absorb the heat, there are few trees to provide shade, and many of the homes are small, old, single-story buildings with little to cushion the heat buildup.
Anita Sworger, a retired blackjack dealer, lived in East Las Vegas, one of the hottest areas of the city, where summer highs average more than 100 degrees Fahrenheit. On June 10, just a few days before a new air conditioner was scheduled to be installed to replace the broken central air conditioner, her son Tristan went to check on her and discovered her dead on the bathroom floor. She was 74 years old.
Bridget Bennett, The New York Times
He had recently installed a window air conditioner in their living room as a temporary measure to protect her from the first heatwave of the season, but the temperature in the poorly ventilated bathroom was probably much warmer than the air outside, says Chima Cyril Hampo, a graduate student at Drexel University who studies indoor temperature.
“It was terrible, the timing was terrible,” Swogger said.
Nighttime temperatures in Las Vegas are particularly dangerous: Studies in Asia have found that hot nighttime temperatures can increase mortality by 10-50%.
Source: National Weather Service, Southern Nevada Health Department
Although the suburbs of Las Vegas are wealthier and a little cooler, there’s no escaping the heat.
While some planned communities, like Summerlin-to-the-West, benefit from heat-tolerant amenities such as outdoor malls with brightly colored sidewalks, artificial ponds, and landscaping with shade-providing trees, much of the city’s new development is an endless string of subdivisions of big-box stores with dark-roofed single-family homes, wide roads, and huge, unshaded parking lots.
Our ever-increasing reliance on air conditioning means that, regardless of region, most of our air conditioners run out of power at night, increasing our electricity bills, emissions, and frequency of breakdowns. (Even when temperatures reach the minimum acceptable temperature, it’s still uncomfortable for much of the night.)
Yancey and Tris Hill live with their 18-year-old daughter and five pets in a three-bedroom home in a middle-class neighborhood in Henderson, a city of more than 300,000 people southeast of the metropolitan area. When their central air conditioning broke in early July, no one was there to fix it right away. Even with the curtains closed, temperatures in the house reached 102 degrees Fahrenheit, and at night it was in the mid-90s. The family got through the week with the help of a $200 swamp cooler and chilled head wraps.
At night, Tris slept with an ice pack under her pillow, Yancy took cold showers before bed, and their daughter slept with their pets in the living room with a swamp cooler.
“It’s been absolutely devastating,” said Yancey, 46, who runs an online retail company and works from home.
Bridget Bennett, The New York Times
Living with the desert
Stephen Lehmann, professor of architecture and urban planning at the University of Nevada, Las Vegas, said that to make cities less hot, day and night, cities must change where and how they grow — that means more walkable neighborhoods, lighter surfaces, more native plants and better-insulated buildings. “We have to embrace this from the inside out,” he said, noting that about a billion people around the world who live in desert cities must deal with extreme heat.
The city plans to plant 700 trees along Stewart Street, about a mile from where Anita Swauger died, a major thoroughfare that crosses some of the metro area’s hottest and most vulnerable neighborhoods. The city plans to plant 60,000 native and adapted trees by 2050. The transportation commission is installing shaded bus stops in hot areas of the city to give riders relief from the scorching sun.
Bridget Bennett, The New York Times
The sweltering heat also afflicts many of the 40 million tourists who visit Las Vegas each year, but the Strip offers plenty of opportunities to beat the heat: outdoor mist sprayers, hotel pools and air-conditioned buildings allow visitors to stay indoors to gamble, dine and shop.
On a recent morning, the temperature had already hit 95 degrees at 9 a.m. in the homeless encampment behind the car wash; it hadn’t dropped below 90 the night before. Blanca Solis, 49, was staying in a purple tent with her boyfriend. She spent the day searching for ice and water, and at night she slept under a brown blanket. Some people pour ice or water over the ground before going to sleep because it’s too hot to touch.
“You can’t even lie down on it,” Solis said.
Bridget Bennett, The New York Times
Ms Solis’ boyfriend, Richard Kettler, who is in his early 40s, said she sometimes wakes up with a “baked in oven headache”.
“It’s so hot I can’t explain it.”