Las Vegas sees record-breaking 7 consecutive days of scorching temperatures 115 degrees or higher

LAS VEGAS, Nev. -- Las Vegas is sizzling under a prolonged heat wave that has delivered a record-breaking seven consecutive days of temperatures 115 degrees or higher amid a historically hot summer in the United States.

"With a high temperature of 115F this afternoon we not only extended our streak to 7 days, but we also broke the daily record high," the National Weather Service in Las Vegas said in a post Friday. "This makes today the 7th day IN A ROW that we have broken or tied daily high temps!"

During the city's punishing streak, Las Vegas saw its all-time hottest temperature on record of 120 degrees on July 7. The city also recorded three consecutive days above 118 degrees - something that has never happened before, according to data dating back to 1937.

It's been the hottest summer on record for around 100 US cities from Maine to California.

Extreme heat is one of the leading weather-related killers in the United States, leaving hundreds of people dead each year, according to the National Weather Service. Heat is suspected in the deaths of least 37 people in the US in July, a number that is likely underestimated.

A motorcyclist died from heat exposure Saturday while visiting Death Valley National Park as the temperature there reached 128 degrees this weekend.

Nearly 104 million Americans are under heat alerts through the start of the week. Swaths of California, Nevada, Arizona and Utah were under excessive heat warnings Saturday.

"This long-duration heat wave remains extremely dangerous and deadly if not taken seriously," the weather service said. "Dozens of daily record high temperatures are forecast over much of the West through Sunday."

Everyone is vulnerable to heat, but some are more at risk than others. Children, the elderly, pregnant people, people with heart or blood pressure issues, outdoor workers or anyone without access to reliable cooling are more likely to succumb to heat-related illnesses than others.

Dangerous and record-breaking heat will continue for much of the West through Saturday, while sizzling temperatures will also begin to build across the Central Plains and Southeast.

Heat will slowly start to ease for much of the West through the weekend as the heat spreads to the East.

While the extreme nature of the heat in the West will start to ease late this weekend, the region is still typically quite hot in July even without heat reaching record levels daily.

The scorching heat will expand over parts of the Middle Mississippi Valley and Southeast on Sunday and Monday.