Margaret Mildenberg of Fort Washington made her annual trip to Ocean City Friday evening, with her car radio broadcasting promises of a warm and sunny holiday weekend.

But yesterday, it drizzled all day. A thick gray fog covered the tips of the city's high rises and a brisk wind blew off the water adding a bitter chill to the 50-degree weather.

And Margaret Mildenberg, like many of the city dwellers and suburban residents who flocked to Ocean City this weekend for sun and sand, found herself spending Saturday in much the same way she does at home - browsing through a covered shopping mall.

Although the weather put a damper on the first day of the summer season here, it marked an auspicious beginning for the Gold Coast Mall, Ocean City's first enclosed shopping center, that yesterday attracted hundreds of visitors in search of a warm dry place and something to do.

"If it was sunny I'd be on the beach. But on a day like this there's nothing else to do but shop," said Janet Shaffer, of Waynesboro, Pa., as she sat on one of the mall's concrete benches holding a blue paper bag from one of the Gold Coast jeans stores.

"My nephew just got in (to Ocean City), and he said we left nice weather at home," added William Zimmerman of Collingdale, Pa. "It was 80 degrees up there, I understand," Zimmer said.

While the throng at the mall browsed through clothes T

Zimmerman said.

While the throng at the mall browsed through clothes and record shops and walk about carrying frozen yogurt cones or slices of pizza, a sparse crowd of mainly teenagers dressed in windbreakers or heavy sweaters walked along the boardwalk.

It was not a good day to test the city's beach, which has been ravaged by 28 northeast storms since Oct. 14. according to Ocean City Mayor Harry Kelley. At high tide, the beach appeared to be no more than 20 feet wide in spots. Over the past few months the city has spent almost $500,000 to restore the beach by using bulldozers to push sand from the surf inland.

A registration clerk at the Carousel Hotel - one of the major oceanfront resorts - said the hotel had received some cancellations from people who had heard that much of the beach had disppeared because of the storms. "One man said, 'If I do come down, where's the beach?'" said the clerk.

Therefore, much of the city's activity yesterday was concentrated at the new and somewhat controversial mall. There, a Dixieland band from Baltimore played continuously and visitors received free ballons, litter bags and T-shirts bearing the name of the mall in gold letters.

Many Maryland political figures, including Senate President Steny Hoyer, Comptroller Louis Goldstein and Attorney General Francis (Bill) Burch, all gubernatorial hopefuls, showed up for the opening day ribbon-cutting ceremony at the ball and heaped praise on the new addition to Ocean City.

But the mall has recived only a lukewarm reception from Mayor Kelley, some of the other city leaders and many mercahnts who fear the mall will divert business from the city's small stores.

"If I told you we weren't concerned (about competition) I'd be lying," said Richard M. Lawes, owner of the Super Thrift supermarket which is a short distance down the road from the Gold Coast Mall. Noting that the new mall includes an A&P supermarket, Lawes said "The trend here is toward the bigger boys, the supers, the chains, the franchises... it's all at the expense of the small independent guys."

Meanwhile restaurants and fast food service owners expressed apprehension over the arrival this season of Ocean City's first McDonalds, Gino's, and Athur Treachers.

But City Council member Harold (Chip) Gordy sees the coming of these well-known chains to Ocean City as an indication that the city is becoming more of a year-round resort.

Gordy said there are now 3,549 year-round residents in Ocean City, "and it's growing all the time." Ocean City's population has multiplied three times since 1970, Gordy said.

In the view of many merchants, the number of annual summer visitors is also increasing and therefore there will be enough business to go around even with the new 40-store mall.

The mall, which resembles almost any of the other malls found in suburban Maryland or Virginia, and has the usual mixture of clothing stores, record and novelty shops and fast food restaurants, was built by Sidney J. Brown. Brown is also the developer of the Beltway Plaza and Hechinger Plaza Mall in the Washington area.

Brown said the built the mall to attract "the Atlantic City type people" who live in the expensive, luxurious condominiums in the city's uptown area.

Many of these condominium owners are well known and wealthy Washington and Baltimore area political figures and business people.