Summer's about to end, but you can still make a spur-of-the-moment Labor Day getaway

We've hardly donned our tank tops and dieted our way into those skimpy swimsuits when, suddenly, summer is almost a fond memory. A Labor Day getaway can give us that last chance to savor the warm weather. As with any vacation, things will go most smoothly if you plan a couple of weeks in advance. But it's also possible to just get up and go (after calling ahead to reserve a room for the night). Here are some last-minute planning tips:

* Although Labor Day weekend (September 1) is a busy time for U. S. resorts, it's offseason in the Caribbean, the Bahamas and Mexico. That means last-minute vacancies, fewer tourists and better prices.

* If you're traveling by plane, make reservations as soon as possible to get the lowest fare. Discount seats are limited and are snapped up quickly.

* Ask your travel agent whether the airline or cruise company offers last-minute travel discounts. For instance, Carnival and Norwegian Cruise Lines have late-booking discounts to the Caribbean and the Bahamas.

* Travel clubs can offer substantial savings to people who are able to pick up and go at a moment's notice. Try Stand-Buys, Ltd. at (800) 255-0200; Moment's Notice in New York at (212) 486-0503; or Vacations to Go at (800) 338-4962. Memberships cost from $20 to $50 and are good for a year of travel bargains.

* State and foreign tourist boards are a good RAH source of information about special events that will be taking place over the Labor Day weekend. Most have toll-free telephone numbers. For directory listings, call (800) 555-1212. The following is a selection of Labor Day getaways for singles, couples and families:

BLUE RIDGE MOUNTAINS, VIRGINIA. Wintergreen Resort. The perfect resort for sports enthusiasts and nature lovers, on 11,000 acres in the Blue Ridge Mountains, has 25 tennis courts, golf, swimming, horseback riding and 25 miles of hiking trails. Recommended for: families. Rates: $528 for four persons in two bedrooms for three nights under the Family Getaway plan, including one night of free baby-sitting. Reservations: (800) 325-2200.