In almost 150 years of record keeping, it has never been as hot in San Francisco as it was on Friday.

Amid a brutal heat wave that has broiled California for a week while intermittently knocking out power to thousands and fueling more than a dozen wildfires, downtown San Francisco hit 106 degrees.

“San Francisco continues to climb. Latest high temperature for downtown is an incredible 106 degrees!” the National Weather Service’s Bay Area station tweeted Friday.

The previous record was 103 degrees, set in 2000. San Franciscans got creative on social media to document their pain.


The Bay Area is on Fire 🔥 today! Lord it's hot! pic.twitter.com/OzlY7UjxBA — B and Mike D Show (@B_MikeDshow) September 1, 2017

The San Francisco Bay Area now. Yes, it's hot. No, we don't have air conditioning. pic.twitter.com/5h8qWztDEl — Peter Gleick (@PeterGleick) September 1, 2017

But that was not even the worst of it for Northern California. By 3 p.m., the East Bay valley cities of Livermore and Pleasanton were at 110 degrees. Livermore was expected to flirt with its all-time record of 115 degrees Saturday — but came up short Friday, reaching 109 degrees.

“When we’re approaching all-time record highs, that’s very unusual,” said Steve Anderson, a meteorologist with the National Weather Service.


The temperature reached 108 degrees in San Jose, breaking the city’s record for Sept. 1 of 101 degrees, set in 1950.

The heat wave marks the finale for what has ended up being the state’s hottest summer on record, UCLA climate scientist Daniel Swain said.

In a tweet, Swain said June through August temperatures were above average everywhere in California except the north coast.

Previous all-time record high in Downtown #SanFrancisco was 103 set on June 14, 2000. High so far today: 106! #CAwx #CAheatwave — NWS Bay Area (@NWSBayArea) September 1, 2017


The heat wave is part of a high-pressure system that’s gripped the West Coast. Virtually no one is being spared.

According to the National Weather Service, 36.5 million residents, or 98% of Californians, were under a heat advisory Friday as a high-pressure system roasted the state from Oregon to the U.S.-Mexico border.

On Friday afternoon, an extremely fast-moving brush fire broke out in the Verdugo Mountains near Sun Valley. Fueled by light grasses, extremely high temperatures and a light breeze, the flames jumped the 210 Freeway and threatened homes, triggering evacuations.

In Northern California, school districts in Los Gatos, Novato and Orinda announced that students would be let out early Friday to dodge the worst of the heat. Outdoor festivals and youth sports leagues also canceled events through the weekend. Concord, Santa Rosa and Antioch, among other cities, have opened cooling centers for the weekend.


36.5 million Californians are under a Heat Advisory/Warning this weekend - or about 98% of the state's population. #CAheat #cawx #heatwave pic.twitter.com/cBSboyqysI — NWS Bay Area (@NWSBayArea) September 1, 2017

In Los Angeles, the Department of Water and Power braced itself for what the utility expected to become its biggest day ever for power demands as residents sought relief from triple-digit temperatures in the valleys, foothills and high desert.

Demand was high but not enough to break a record set just the day before, officials said.

On Thursday, the DWP announced that its customers used more electricity than ever in the agency’s history. Customers hit a peak demand of 6,502 megawatts at 4:15 p.m., shattering the previous record of 6,396 megawatts on Sept. 16, 2014.


The statewide demand led the California Independent System Operator to issue its fourth flex alert of the year, calling for voluntary electricity conservation.

DWP officials advised residents to set their thermostats at 78 degrees or higher and to use major appliances before or after peak hours. They also said that turning off unnecessary lights would go a long way toward reducing the strain on the utility’s electrical equipment and overall power system demand.

1 / 29 Crissie Sumerlin, a visitor from Baltimore, takes in the view and the cool breeze at Santa Monica Pier as a heat wave continues to bake Southern California. (Luis Sinco / Los Angeles Times) 2 / 29 Jasmine Ejan cools off with a cone of chocolate ice cream on a warm afternoon in Venice Beach. (Luis Sinco / Los Angeles Times) 3 / 29 A vendor shelters from the sun while selling umbrellas, beach towels and boogie boards along the boardwalk near the Santa Monica Pier on a warm Southern California afternoon. (Luis Sinco / Los Angeles Times) 4 / 29 Mariachi player Natolio Nuñez, who has been playing trumpet for 40 years, practices in the shade while silhouetted against a mural amid a heat wave where temperature reached 93 degrees at Mariachi Plaza de Los Angeles in Boyle Heights. (Allen J. Schaben / Los Angeles Times) 5 / 29 Rain falls behind power lines near Adelanto at the end of a scorching hot day. (Luis Sinco / Los Angeles Times) 6 / 29 Cumulus clouds frame Disney Hall in downtown Los Angeles as scorching heat continues across the Southland. (Allen J. Schaben / Los Angeles Times) 7 / 29 Isaac Padron, 24, of Canoga Park, cools off, while taking a break from skateboarding at Lanark Park. (Mel Melcon / Los Angeles Times) 8 / 29 Lilly Santiago, 5, left, cools off with her mother Lupita, 56, after playing basketball at Lanark Park on Thursday. (Mel Melcon / Los Angeles Times) 9 / 29 Mariachi player Natolio Nuñez, who has been playing trumpet for 40 years, practices in the shade in Mariachi Plaza in Boyle Heights. (Allen J. Schaben / Los Angeles Times) 10 / 29 Sophia Madrigal, 5, cools off at the Sylmar Recreation Center. (Al Seib / Los Angeles Times) 11 / 29 Crystalie Merino, 23, does her cardio workout in triple-digit heat in Warner Park in Woodland Hills. (Al Seib / Los Angeles Times) 12 / 29 Josh Navarro and niece Frankie, 2, enjoy Lyle Creek in San Bernardino. (Irfan Khan / Los Angeles Times) 13 / 29 Keeping cool in the Grand Park fountain in downtown Los Angeles. (Allen J. Schaben / Los Angeles Times) 14 / 29 Kenia Rivera, 26, sits in the shade in Lyle Creek in San Bernardino with Alex Navarro, left, and Jacob Navarro. (Irfan Khan / Los Angeles Times) 15 / 29 Reginaldo Ramirez gulps cold water after working in San Bernardino, which hit 111 degrees on Wednesday. (Irfan Khan / Los Angeles Times) 16 / 29 Workers toil in 111-degree temperatures in San Bernardino. (Irfan Khan / Los Angeles Times) 17 / 29 A windsurfer at Cabrillo Beach in San Pedro. (Luis Sinco / Los Angeles Times) 18 / 29 Edgar Eduardo Herrera drinks from a fountain at Exposition Park in Los Angeles, where the mercury reached into the high 90s. (Luis Sinco / Los Angeles Times) 19 / 29 A woman shelters in the shade of the entrance to the California Science Center in Exposition Park. (Luis Sinco / Los Angeles Times) 20 / 29 Edwin Cruz of Los Angeles sells cotton candy and toys to families at Whittier Narrows Recreation Area in South El Monte on Sunday. (Allen J. Schaben / Los Angeles Times) 21 / 29 Kids play in the water at Whittier Narrows Recreation Area. Forecasters said a record-breaking heat wave will linger in Southern California until at least Thursday. (Allen J. Schaben / Los Angeles Times) 22 / 29 Kids play in the water at Whittier Narrows Recreation Area in South El Monte on a hot Sunday. (Allen J. Schaben / Los Angeles Times) 23 / 29 Gilman Orozco and his son Ian Orozco, 2½, both of Los Angeles cool down in a hammock at Frank G. Bonelli Regional Park in San Dimas on Sunday. (Francine Orr / Los Angeles Times) 24 / 29 To cool off, Jeffery Sofia Puga, 3, left, with her father Carlos Puga, 23, both of Torrance, eat ice cream and soak in the lake at Frank G. Bonelli Regional Park in San Dimas. (Francine Orr / Los Angeles Times) 25 / 29 Victor Dudchenko tosses his friend’s daughter Julia Bogachuk in the air while they play in the lake at Frank G. Bonelli Regional Park in San Dimas. (Francine Orr / Los Angeles Times) 26 / 29 Visitors cool down in the lake at Frank G. Bonelli Regional Park in San Dimas on Sunday. (Francine Orr / Los Angeles Times) 27 / 29 Luis Alvarez swings in a hammock with his 11-month-old son, Adrian Alvarez of Los Angeles, in the shade at Whittier Narrows Recreation Area. (Allen J. Schaben / Los Angeles Times) 28 / 29 Kids fish and play in the water at Whittier Narrows Recreation Area in South El Monte. (Allen J. Schaben / Los Angeles Times) 29 / 29 A person is silhouetted while relaxing in a tent by the water at Whittier Narrows Recreation Area in South El Monte. (Allen J. Schaben / Los Angeles Times)

Woodland Hills reached 111 degrees Friday, tying its daily heat record set in 2007. It was 102 degrees in downtown L.A., but that failed to eclipse the record, set in 1950, of 110 degrees.


In Riverside, the mercury peaked at 112 degrees, breaking the city’s record of 111 degrees, set in 2007. Ramona was not far behind at 109 degrees, breaking its record, set in 2002, of 107.

Similar temperatures were reported across the San Joaquin and Sacramento valleys.

“Even the typical cool coastal areas will be subjected to much warmer than normal temperatures as the usual onshore flow saving grace becomes nonexistent,” the National Weather Service wrote in a Friday morning forecast.

Just a reminder. Avoid Heat Illness by following a few good tips. Hi temps are expected to reach 108- 114 in some locations. #cawx #LAheat pic.twitter.com/mJnsBk1xqU — NWS Los Angeles (@NWSLosAngeles) September 1, 2017


The heat wave is expected to break in Southern California on Saturday and in Northern California on Sunday, but more warm weather is expected next week, forecasters said.

The high-pressure system driving the heat wave is also at least partially responsible for the behavior of the storm Harvey in Texas, said Bill Patzert, a climatologist with NASA’s Jet Propulsion Laboratory. The system acted as a barrier that blocked Harvey’s path inland. The storm was stopped in its tracks right over Houston, where it continued sucking up moisture from the Gulf of Mexico and raining it down on the flooded landscape below.

“Until the large-scale pattern changes, it will continue to soak Texas,” Patzert said.

joseph.serna@latimes.com


For breaking California news, follow @JosephSerna on Twitter.

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UPDATES:

9:45 p.m.: This article was updated with additional information on heat and power use records.

5:40 p.m.: This article was updated with new heat records set across the state.


4:00 p.m.: This article was updated with reports of broken heat records in Northern California.

This article was originally published at 11:50 a.m.