West endured another day of 100-degree heat and threats of rolling blackouts

Millions of people across the western United States endured punishing triple-digit temperatures, as power companies pleaded with their overheated customers to be judicious with electricity use Wednesday.

The temperature climbed to 109 degrees in Sacramento, California; 99 in Los Angeles; 107 in Salt Lake City; 99 in Grand Junction, Colorado; and 107 in Las Vegas in a heat wave that's expected to last the rest of the week.

Sacramento, Salt Lake City and Grand Junction hit record highs for any Sept. 7.

Amazingly, Wednesday's record-setting scorcher in California's capital represents a small dose of relief: Tuesday hit an all-time high of 116 degrees. Before this year, Sacramento had never recorded a September temperature at or above 110 degrees, and now the city has hit that sweltering mark two days out of three.

The Sacramento Municipal Utility District thanked its "incredible customers" for conserving energy Tuesday.

"With your help, we were able to avoid rotating outages," the utility said in a statement late Tuesday. "We still have 3 more days of 100+ degree weather ahead, so please continue to reduce energy usage from 4 p.m. to 9 p.m."

Sacramento is far from alone in its heat-related misery.

  • The Southern California temperature was expected to remain in the high 90s Thursday and Friday. And with the addition of high winds, 59,982 Southern Califorina Edison customers "are under consideration for" pre-emptive power shutoffs late Friday and early Saturday, a utility spokesman said Wednesday night.

  • Before Wednesday's 107-degree reading, Tuesday's high temperature of 105 in Salt Lake City marked the hottest September day in the city's history.

  • Grand Junction, which sits at 4,600 feet above sea level near the Utah border in far western Colorado, recorded 101 degrees Tuesday, the hottest September day on record.

  • The dry heat has also placed about 13 million people in the West under fire alerts Wednesday, especially across much of Montana where tens of thousands of acres were burning.

  • There were nearly 24,000 Pacific Gas and Electric Company customers in the Bay Area without power Wednesday evening, mostly in and around San Jose, where temperatures reached 97 degrees.

  • There were more than 4,400 customers without power in the Silicon Valley community of Palo Alto on Wednesday morning. The outage turned out to be the work of a squirrel getting into underground cables, officials said.

It was 99 degrees at first pitch for the San Francisco Giants-Los Angeles Dodgers game in downtown L.A. and future Hall of Fame pitcher Clayton Kershaw said he wanted to work fast.

There were swaths of empty seats, despite the paid crowd of 39,237, as fans sought any shade they could find at Dodger Stadium.

"It was hot out there. I tried to just go quick," Kershaw told reporters after his team's 7-3 victory. "Thankfully, I had some quick innings early on."

The unbearable heat did no favors for first responders and Placer County residents fleeing the out-of-control Mosquito Fire, which had consumed at least 4,4223 acres by Wednesday eventing with zero containment.

It reached 104 degrees in Gold Country as sheriff’s deputies are enforcing mandatory evacuation orders.

"You're here to work for these people, these citizens of Foresthill, a couple thousand of people that are depending on us to save their community today," Cal Fire Division Chief Mike Rufenacht told a gathering of first responders gathered at Foresthill High School.

"This fire is going to pick up today, OK? Do not lean back on your heels today. This fire is going to burn very aggressively."

Even in the face of triple-digit heat, an out-of-control fire and mandatory evacuations, the firefighter said he hopes high school football will still be played this week, just feet away from where he stood.

"Let's put in some hard work today, you guys, get some things done, save this community and get these kids playing football this Friday night out at this field," he said.

This article was originally published on NBCNews.com