You could hardly persuade Korry Obain that shorts aren't the thing to wear this summer. She clinched the biggest order for her new rental banquet tablecloth business with the Hilton Hotel last week when she was wearing shorts. She travels the shuttle to New York wearing shorts, and drives her van wearing shorts.

Obain is not unique. Shorts have become Washington's hot hot-weather uniform. Hardly the variety that designers trot out each season to spice up their warm-weather collections, the current styles spring mostly from serviceable surplus styles, camp shorts and even track shorts.

Washingtonians have long been used to tennis and jogging shorts. So the wearing of shorts for leisure and work is more natural than, say, miniskirts, which are having a revival in London and Paris this summer and are being seen far more frequently in Manhattan than here.

Mirtha Savage, Lucite jewelry designer, started wearing shorts around Washington in the summer about four years ago. Her choice then, as now, were the white British Navy shorts. Now, however, she feels far more confident since so many others are wearing shorts. The only place she won't wear them, she says, is to parties with her husband's colleagues in the law business. Then she opts for a conservative dress.

"I'm a tennis player and I've always worn shorts," says Margo Carper, a graduate student at Catholic University. She wears shorts to work at John Henry's, where they are sold in great quantities. "There are so many more varieties of cuts and colors and even shape with pleating, I feel I can wear them anyplace." On the other hand, Limor Joseph, a Montgomery College student who works as a waitress at Oscar's in Rockville, wears shorts everyplace but to work, where they are forbidden.

Howard University student Donna Moragne says, "I wore plenty of them last year but mostly around the house. This year I am comfortable wearing them publicly."

Confirmed shorts wearers, hooked by the comfort and ease, even wear them out to dinner. Says Joe Moriarty, buyer and manager of Moss Brown in Georgetown: "You know, it never occurred to me not to go to dinner in shorts. But then maybe I never go to the kind of place that would not permit them."