You never know who'll you run into at the super deluxe disco, Studio 54. Given their chilly relationship, it's unlikely that Jacqueline Onassis had expected to run into Christina Onassis, daughter of Jackie's late husband, shipping magnate Aristotle Onassis. Christina arrived with friends about the time Jackie was leaving. Earlier Jackie Onassis had been at the gala benefit for which she was co-chairman with artist William Katz.

Also at Studio 54, according to one of the regulars, a mix of punks, hairdressers, socialities and suburbanites all enjoying the anonymity of the huge dance floor and the extraordinary sound and light show.

One place you don't see any punkdress - unlike Paris - is on the runway of the current fashion shows in New York. "There is no punk fashion in New York," says Lynne Franks, owner of the London boutique Mrs. Howie. "Americans are reading punk as political, but with the London kids it is strictly fashion." Her husband, designer Paul Howie, agrees. "It was political when it started a year to so ago, but now it is just a look - the way Mods and Rocker and hippies became a look," Howie said. Punk is now so widespread in London you see it everywhere. "Three of the kids on our staff have started dressing punk," says that deal with the public. "It just doesn't go with the look of our clothes."

Not so dumb, these fashion people, when put to the test by bad weather. For the torrential rains that plagued the ity during last week's spring showings, for example, Andre Leon Talley of Women's Wear Daily slipped a rain suit over his clothes and donned fisherman's boots. New York magazine's Priscilla Tucker was head-to-toe in a nylon ski coversing worn over everything including her backpack. Other smart moves: the rubber riding boots worn by several buyers and the L.L. Bean-type rain ponchos and sewer shoes for others.

The spring color scheme goes from pale to pale, the best of them face powder colors, then pinks into grays and a fair share of baby blue. The best prints are on the fragile side, too, like Calvin Klein's rosebud prints, the tiny stripes at Cathy hardwick and Geoffrey Beene's geometric pin-dots and plaids.

As it was in Paris, some of the spring clothes being shown on Seventh Avenue are so see-through that even seams of pantyhose, worn with not-a-thing underneath, show through. "Our customers will wear them with pretty crepe de chine slips," says Kay Kerr of Neiman-Marcus. Donna Gromet, the young sportswear buyer from Montaldo's, who is originally from Silver Spring and graduated from High Point High School in Beltsville and the University of Maryland, sees her customers wearing camisoles under the very bare tops.

Replacing last season's frizzy-headed models at some of the shows (though not at all of them) was shoulder length or longer soft, curly hair - very sexy, quite Rita Hayworth looking - or else over the face. They styles are casual enough to look like the models had done their own coifs, which is, of course, the way the hairdressers intended.

Makeup on the runway, always an indicator of what's to come, remains very natural looking, (Remember, it was the natural look that used to take Marilyn Monroe three hours to put on) At Calvin Klein's show, the models wore Klein's cosmetics, his next venture, all applied in the most natural way by Way Bandy.

Geoffrey Beene showed his menswear last week, mostly unconstructed cotton suits or big tops, much like he shows for women, with his models wearing Adidas. They are not spanking new smeakers or running shoes but the well-worn athletic shoes and male models were all the time themselves.

Adri is a name that hasn't been around Seventh Avenue for a while - she's been successfully designing longewear for Royal Robes. But last week she resurfaced as the designer for Silverman Sport, and it should be a good partnership. She has always been partial to easy, comfortable clothes, wrap skirts with big patch pockets, and the like, very much in the manner of the late Claire McCardell. That puts her completely in step with Seventh Avenue today.

Bill Blass has a new abstract painting on displayin his showroom. It was painted by local artist Ann Purcell, whose work Blass sported at the Corcoran Gallery of Art on his last visit to Washington for a fundraiser for the gallery.

When is a dress a simple it is barely designed at all? Maybe that is a fair question to ask about some of the chemise and tent styles - simply a layer of fabric covering the body - showing up in a number of the collections. They are bound to be favoraties for the home sewer who is likely to find that tiny details will separate the home made versions from the designer label styles.

One of the strongest sellers at the London designer collections was the very sexy intimate appacel from Janet Reger in spite of the fact that some stores calculate they will have to sell the items here at seven times the wholesale price from London because of the import duty on a laces.

Clarification: Those Hazae Mori designs shown in New York recently and at the Japanese embassy on Thursday are sold in many stores including Neiman-Marcus, where they will be presented tonight for the benefit of the International Student House. Among the Hanae Mori collectors are Grace Kelly, Dewi Sukarno, Imelda Marcos, and others.