By 1 p.m., it was 94 at Redondo Beach, 93 at Fullerton and 89 at USC. Unofficial NWS weather stations at Malibu Hills and Leo Carrillo Beach in Malibu showed 90 degrees.
The forecast high for the coastal strip was around 92 degrees at the beaches -- the hottest places during offshore wind events like this, the National Weather Service said.
The valleys, foothills and deserts were to be a relatively-cool 88-degrees.
The conditions are expected to drive an estimated 750,000 to 1 million people to beaches along the 37 miles of coastline under the watch of county lifeguards between Zuma Beach and Redondo. A similar number of beachgoers could take to the shore from Redondo to San Clemente.
"We are experiencing large crowds and we've staffed out towers accordingly, Los Angeles County Fire Department Lifeguard Capt. Kenichi Haskett said.
The National Weather Service expressed special concern for people who'll take part in Sunday's L.A. Marathon, saying they need to be aware of the potential for serious heat-related problems.
Given the hot weather and onset of Spring Break season, more lifeguard towers will be open than typical for this time of year and seasonal lifeguards also were being deployed earlier than usual, he said.
"The surf is cooperating. It's not causing significant rip currents," Haskett said.
Wave heights were two to three feet and the water temperature was a summer-like 63 degrees.
NWS forecasters urged residents and visitors to avoid heat stress, including by scheduling outdoor activities in the morning or evening to avoid the day's strongest heat, wearing light clothing if engaging in strenuous activities, and staying hydrated.
They also urged residents to "never, ever leave children, pets or the elderly alone in the car."
Meanwhile, on Friday, record temperatures of 92 were reached in Long Beach and Santa Ana, breaking the 89 degrees both cities experienced in 1994.
Downtown Los Angeles set a record of 90, topping 89 in 1994. UCLA's 87 tied a record, also set in 1994.
Highs were expected to begin a slow downward trend on Sunday, and generally revert to the 70s starting Tuesday.