Temperatures Cool Off to a Great Degree : Weather: The heat is bringing an early start to the brush-fire season, officials say. Water use, however, was not as great as expected.

Orange County, bedeviled by record-setting temperatures over the weekend, had somewhat less trouble keeping its cool Monday with a double-digit drop in highs and a return to a more normal weather pattern.

The high in Santa Ana was 79 degrees, 21 degrees below Sunday’s 100-degree topper. Anaheim, however, remained a toasty 91 degrees.

Meteorologist Steve Burback of WeatherData Inc., which provides forecasts for The Times, said Anaheim and other inland areas received little relief because the marine layer of moist, cool air that doused the heat spell along the coast failed to reach those regions.

The temperature at the Los Angeles Civic Center, where the thermometer hit a record 101 over the weekend, was 79.

It is expected to be even cooler today in the Los Angeles Basin, with the marine layer expected to return again along the coast, producing night and morning cloudiness and hazy afternoon sunshine.

Burback said a pair of high-pressure ridges centered over Central California and Utah’s Great Basin that produced the weekend’s sizzling highs has been replaced by cooler air moving southwest into Southern California.

As the weather shifted toward normal, so did the scene at Southland beaches, where hundreds of thousands sought relief from the weekend of “superheat,” as one forecaster called it.

On beaches from Venice and Santa Monica to Topanga Canyon, where an extraordinary pre-summer crowd of about 500,000 people collected Sunday, Los Angeles County Lifeguard Lt. Ira Gruber placed Monday’s total at a fraction of that.

“I’d say we have about 10,000 today,” Gruber said.

Up the coast, where an estimated 164,000 gathered Sunday on beaches from Zuma to Malibu, Senior Lifeguard Jim Jacobson said Monday’s crowd was “about normal” for a workday while school is in session. He estimated that about 20,000 sunbathers showed up Monday.

In Orange County, where more than 110,000 showed up at Huntington Beach on Sunday, Lifeguard Supervisor John Blauer estimated the crowd at about 6,000 on Monday. In San Clemente, about 4,000 people lounged on the city’s two-mile stretch of sand, as opposed to 15,000 on Sunday.

The weekend’s hot weather brought the drowning deaths of four teen-agers.

The victims were identified Monday as Kydieu Truong, 17, of Monterey Park, who was caught in a strong riptide at Hermosa Beach; Juan Martinez and Elias Caracoza, both 18 and of North Hollywood, who became entangled in weeds at Castaic Lake, and Orlando Gonzalez, 18, a Hollywood High School student, who drowned at Santa Fe Dam Park Recreation area in Irwindale.

Some Southern California water officials were surprised that water use held fairly steady and below expected levels over the weekend. A spokesman for the Metropolitan Water District, which supplies about 60% of the water in a six-county area of Southern California, said its water deliveries peaked Sunday at 7,369 acre-feet of water. Officials had suspected that usage would easily exceed 8,000 acre-feet.

In some areas of the Southland water usage did go up over the weekend, but it began to head back to normal on Monday, officials said.

Orange County water districts reported substantial increases in water use during the weekend, but the high demand, water managers said, probably will not have an impact on overall supply despite current drought conditions.

“Demands have increased substantially and especially during the weekend,” said Karl Seckel, assistant manager of the Municipal Water District of Orange County. “We used up some of our water in storage, but it is insignificant compared to the amount used for the year.”

Seckel said it is difficult to assess what impact the surge of heat has had on the entire water supply of Orange County.

Firefighters said the heat spell helped hasten the beginning of the fire season in Orange County, drying out hillside vegetation in about three days. Normally, browning of the hills would take another month or two, said county Fire Capt. Joe Kerr, a wild land fire defense planner.

Times staff writers Jeanette Avent, Stephanie Chavez and Bettina Boxall contributed to this story.