It was too cold yesterday to do much at the shore, too early for a colorful cruise through the mountains, too late to mow the grass, too soon to rake leaves, and in Maryland the kids had school.

Reasons enough to make Columbus Day a success for Washington merchants, says Leonard Kolodny, manager of the retail bureau of the Greater Washington Board of Trade.

Not yet a rival to Washington's Birthday, Columbus Day is becoming an increasingly important date on local retail calendars because the federal employes' holiday is creeping into private industry, he explained. Many government contractors already have adopted the day off, and now Columbus Day is being observed by other white collar employers who compete with the government for clerical workers.

Three-day weekends generally aren't good for retail sales because many families leave town, but with schools in session in the Maryland suburbs, the parents have time to shop, Kolodny added.

Though yesterday's crowds were far from Christmas-size, the cold snap was like a gift for clothiers who've yet to find a way to make customers buy winter coats before the weather turns cold.

Most stores could stand a little good news, for with some conspicuous exceptions retail sales have been sluggish for months. The exceptions include home-improvement items and higher-priced clothing which has produced a fantastic fall for Saks Fifth Avenue and its competitors in the designer and couture business. Shoes also have been moving well.

At the opposite end of the price picture, the going-out-of business sales by Korvettes are making competition tough for stores trying to make a normal profit when the entire inventory of four Korvettes stores is being dumped at a loss.

Washington retailers blame their flat fall sales charts on pre-presidential-election jitters, the general malaise in the economy and the weather.

But the weather finally is turning cold.