Hats

Nearly every model on the runways at showings in New York, Paris, Milan, and London wore a hat. This was in contrast to the audience, where the majority went hatless.

Now is no time to underrate the future of millinery. Quite the contrary. Hats are really making headway. That has been said before, again and again, but circumstances in the past weren't as favorable for hats as they are today.

Hairstyles weren't close to the head. The lines of the silhouette weren't so long and drawn-out, and therefore in need of the balance of a hat. And women weren't as conscious of the importance of a finished appearance.

This spring designers, in their wisdom, forcast a booming season for hats.

At the top of the list is the sailor, otherwise known as the boater. First choice of Yves Saint Laurent and Oscar de la Renta, among others, it has a long and fond tradition. Coco Chanel loved it so much she wore it herself.

''It does have a spring attitude,'' says New York milliner Frank Olive, whose high-crowned boaters appeared at the showings of de la Renta, Adele Simpson, Adri, Trigere, and Don Sayres. ''I always say, What is spring without a sailor?''

His assortment includes a linenlike balibuntal, a fine peribuntal, and what he describes as ''crunchy textured Milans'' sometimes combined with shiny lacquered straw.

Brims go from 2-inch to 9-inch and colors from vivid yellow, red, or royal to soft pastels. Grosgrain bands are occasionally of racy stripes, as on the sailor he made for Adele Simpson, which is now selling like the proverbial hotcakes across the country.

During last summer's heat spells, a number of New Yorkers rediscovered the benefits of the big-brimmed straw as a sunshade.

A style like the romantic planter's hat shown by Ralph Lauren and Calvin Klein is likely to grace city streets this year. The wide, slightly curved brim not only flatters, but also has its practical side.

Besides the sailor and the planter there's a new brimless straw with a high fashion rating. It's a puffy side-tilted version of the beret; Olive calls it ''The Muffin.'' A pert accompaniment for a short hairstyle, it adds a dashing accent to a spring dress or suit.