As forecasters said temperatures could drop to freezing in downtown Los Angeles overnight Saturday, a preliminary record low was recorded at Long Beach Airport Saturday.
It was 36 degrees in at the airport, tying a record set in 1966, according to the National Weather Service.
Some of the coldest temperatures recorded Saturday morning were in Lancaster and Palmdale where it was 20 and 19 degrees, respectively.
Local news from across Southern California
The chilliest night of this lasting cold snap is expected to be Saturday night into Sunday morning. Frost and freezing temperatures will be widespread west of the mountains to within a few miles of the coast, the National Weather Service reported.
A freeze warning is in effect until 8 a.m. Sunday for the valleys of San Bernardino and Riverside counties, the service said. A high wind watch was also in effect for the Santa Ana, San Gabriel and San Bernardino mountains.
In coastal Orange County, a frost advisory is in effect until 8 a.m. Sunday, while the same advisory is in effect for 1 to 9 a.m. Sunday in Los Angeles County.
Some areas of coastal valleys could see temperatures in the low to mid-20s. Downtown Los Angeles could see freezing temperatures, the weather service said.
Forecasters also warned that the chilly temperatures could cause significant damage to unprotected plants and crops. The cold threatened avocado crops as people are planning Super Bowl parties.
In the mountains north of the Los Angeles, meanwhile, it was only when temperatures rose above freezing that the California Highway Patrol reopened the Golden State (5) Freeway through the Grapevine.
A trial run escorting motorists through Castaic proved successful early in the morning, then northbound and southbound lanes of the freeway over the Grapevine Summit were re-opened as of 7:25 a.m., according to the CHP.
The route was closed at 3:15 a.m. due to snowy and icy roads, but motorists began being escorted over the Grapevine as of 7 a.m.
Until the escorts began, northbound traffic had been diverted at Parker Road and southbound traffic at Smokey Bear Road, according to the CHP.
It was the second time in the past three days that officials closed the main artery linking Southern California with the northern part of the state.
Snow and icy conditions prompted a closure in the same area around 4 p.m. Thursday, stranding thousands of motorists. Some drivers parked overnight after snow and ice blanketed the road late Thursday. Several crashes and spin-outs were reported.
The interstate was reopened at 7:30 a.m. Friday, but only with CHP escorts, Caltrans reported.
An alternative route for northbound travelers was the Antelope Valley (14) freeway north to State Route 58 west toward Bakersfield.
A second alternative was to head north on the Ventura (101) Freeway and travel to the Santa Maria area before heading east on State Route 166 toward Bakersfield.
City News Service contributed to this report.