Geoffrey Beene missed the White House dinner for Danish Prime Minister Poul Schlueter and his wife Lisbeth -- his plane was delayed three hours in the thunderstorm. But he is not likely to miss another diplomatic dinner, one Dec. 3 at the American Embassy, where his clothes will be presented by our new ambassador there, Joseph Rogers, and his wife. In previous years the Beene clothes have been shown in Vienna, Rome, Brussels and in 1978 Paris.

Beene, who makes some of the cleanest, most untricky and modern clothes around, is counting on major changes in clothes in the future coming from the test tube. "We're almost at the point in fashion," says Beene, "where clothes will be chosen by how well they perform, not only what they look like." He hopes a new fabric, developed by Toray Industries in Japan (the makers of Ultrasuede) will be a technological advance over current fabrics. Beene will be the first American to use that fabric -- Issey Miyake uses it in Japan.

Earlier this week Beene was guest of honor at a luncheon at the governor's mansion in Honolulu and presented his collection at Liberty House. But there was more to the Hawaii trip. Beene says it has given him lots of ideas for designs for hot weather with lots of bareness and the use of Spandex.