Sizzling Sunday Sneaks Up on L.A. : Weather: Near-record high of 98 is more than 20 degrees above normal. Thousands find relief at the beaches.

Summer surprised the Southland on Sunday, baking Los Angeles with a near-record 98-degree high downtown.

The searing temperatures, which fell one degree short of the downtown record set in 1923, were abnormally high for early May, said Steve Burback of WeatherData Inc., which provides forecasts to The Times.

“You would expect to see temperatures at about 73 degrees this time of year,” Burback said. “This (hot weather) gradually built its way up for a few days and Sunday ended up being the hottest.”

Slightly cooler temperatures are expected today, with a Civic Center high in the upper 80s, temperatures in the mid 70s along the coast and highs up to the low 90s in the San Fernando and San Gabriel valleys. The normal morning low clouds along the coast will reappear by Wednesday, Burback said.

More than 500,000 people seeking refuge from the heat packed the county’s beaches Sunday from Cabrillo Beach in San Pedro to Zuma Beach in Malibu, where temperatures were in the 80s.

“This is a good crowd for the beaches, especially for a non-holiday,” Los Angeles County lifeguard Capt. Bob Buchanan said. “There are a lot of people in the water, which is about 65 degrees.”

The dry heat kept the skies over Los Angeles cloud-free for part of Sunday, with little breeze blowing in the city or even near the coast.

Farther inland, more than 100 Los Angeles County firefighters battled the hot weather as well as a quarter-acre brush fire at Walnut Creek in San Dimas. No homes or people were harmed by the blaze, which was contained in about 40 minutes, said Fire Department spokesman Lawrence Beals. County fire officials were not certain of the cause of the blaze. Beals said there were no other brush fires in the county.

In Orange County, more than 65,000 people flocked to Huntington Beach, second only to last weekend in crowd size this year, officials said. The heat may have been responsible for smaller than normal crowds at Mile Square Regional Park in Fountain Valley. Only about 1,000 cars--about one-third the volume of a busy Sunday--had driven through the park gates by 4 p.m., park attendant Jeff Dekker said.

“It’s been weird,” Dekker said. “There are not enough trees or shade in our park I guess.”