Southland Sweats Out Sizzling Cinco de Mayo : Heat: Anaheim’s 98-degree high is hottest for date in 37 years. Thousands swelter through holiday festivities.

Record temperatures baked Orange County and the rest of the Southland on Saturday as thousands headed for the cooling waters of the Pacific or choose to take the heat at a host of Cinco de Mayo celebrations.

Light wind and a stationary high-pressure system sent the mercury soaring to 101 degrees in Los Angeles and 98 in Anaheim, the highest readings for May 5 in both areas in 37 years, according to the National Weather Service.

“It’s hot,” said Louise Diaz, with a pineapple Popsicle in hand. Diaz, wearing a full-length, long-sleeved ruffled dress, was waiting to perform Saturday with the Folklorico La Fonda dance troupe at the Mariachi Festival in downtown Santa Ana.

Weather forecasters said the 100-degree temperatures were not expected to return today. Steve Burback, a meteorologist with WeatherData Inc., which supplies forecasts to The Times, said the high-pressure system that spanned from San Francisco to Nevada’s Great Basin would move eastward, leaving a few clouds and highs in the upper 80s and low 90s today.

Temperatures are expected to return to seasonal norms Monday when a marine layer with cool, moist air and onshore breezes is to resume.

Air quality was rated unhealthful Saturday, according to the South Coast Air Quality Management District. The AQMD predicted the conditions will continue today.

In Orange County, tens of thousands of people sought relief at the beaches, where lifeguards described the weather conditions as near-perfect. Air temperatures ranged from 70 to 75 degrees and the water was an inviting 68 degrees. Winds were light; the surf a paltry two feet.

“Conditions are ideal,” said Newport Beach Marine Safety Officer Mitch White. “It’s a beautiful sunny day, there is hardly any wind, the water is warm and there are Cinco de Mayo parties along the beach.”

Crowd estimates ranged from almost 90,000 in Newport Beach to 5,000 in Laguna Beach. Huntington Beach lifeguards said attendance was moderate to heavy. And in Seal Beach, lifeguards reported a crowd of about 10,000, only 2,000 less than the average daily attendence for July through September.

The perfect conditions were marred by coastal roads clogged with carloads of sun-loving beach-goers and a few minor encounters between lifeguards and rowdy beer drinkers. Authorities reported a handful of first-aid calls and rescues involving children.

Los Angeles County lifeguards reported crowds ranging from 100,000 at Long Beach and Hermosa Beach to 90,000 at Zuma. In Santa Monica, an estimated 150,000 shoreline visitors lounged on the sand.

About 2,000 customers in Laguna Niguel lost electrical power for about half an hour Saturday afternoon because excessive demand from air conditioners knocked a circuit out of service, said Steve Sullivan, spokesman for Southern California Edison Co.

Elsewhere in the county, Latinos and aficionados of Mexican culture sweltered in the heat at Cinco de Mayo celebrations to mark the victory of a band of heavily outnumbered Mexicans over the French at Acutzingo Peak in Puebla, Mexico, on May 5, 1862.

Perhaps the largest observance was at Centennial Regional Park in Santa Ana, where the only real relief from the 93-degree temperature were cold drinks, beer and the banks of the park’s small lake.

Typical of the Cinco de Mayo events were singing, folk dancing, carnival rides, Mexican food and music, including the first mariachi festival held in Orange County, which began Saturday at Santa Ana’s Fiesta Marketplace.

At UC Irvine, activities included “Noche de la Raza,” a student theatrical production chronicling Mexican history through music.

Thousands of people milled around the grounds of Centennial Park, where advertisers’ huge inflated beer cans and cigarette packs stood like sentinels over the crowd.

Bands played from two stages. Revelers sampled Mexican cuisine, guzzled beer and queued up for games and prizes at dozens of display booths, including “El Mundo de Drackett” (The World of Drackett), where people tossed rings over plastic bottles of Drano drain cleaner in hopes of winning them.

Others waited patiently for free spinal exams from several chiropractors, who set up temporary shop on the park’s field. Those without a penchant for Mexican food dined on “beef on a stick” and Thai-Chinese food.

At Fiesta Marketplace, 4th Street was closed to cars between French and Birch streets, allowing people to gather and wander through the street to listen to mariachi music, buy tacos or have their faces painted.

Booths offered information on everything from cosmetics to becoming a police officer, but the longest line was at a booth selling state lottery tickets. Except for one drunken man who was escorted away from the stage by police, there were no incidents by late afternoon Saturday.