THE GROUNDHOG is due to lumber from its winter quarters on Feb. 2, and a number of area naturalists are ready. On that day and before they'll be presenting children's programs that explore the facts about the animal and the folklore surrounding its weather-predicting abilities.

Originally, says Melanie Marshall of the Meadowside Nature Center in Rockville, "Groundhog Day had nothing to do with groundhogs."

Marshall explains that German farmers settling in the New World brought their Old World superstitions with them. According to European folklore, on Candlemas Day (Feb. 2) the badger would emerge from his winter home to foretell the weather. In this country, the honor of carrying on the tradition was transferred to the groundhog.

No one is certain how Candlemas Day -- originally set aside by the Catholic Church as a commemoration of the purification of the Virgin Mary -- and animal weather forecasting became intertwined. Somehow we are left with the notion that if the weather on that day is bright, clear and cold, the groundhog will see his shadow, want to go back to bed and we can then expect several more weeks of wintry weather. But if he awakens to find a drizzly, overcast day, we might get lucky with an early spring.

Regardless of how we arrived at today's custom, groundhogs are interesting little creatures to study. The furry mammals are woodchucks, but they're called groundhogs in certain regions of the country and are sometimes called whistle-pigs as well, since they whistle to communicate with each other.

Woodchucks are true hibernators, that is, they eat from the time they end their winter sleep until the following fall, accumulating fat to live on during the coming winter. During their slumber they appear to be almost lifeless. Heart rates slow from 150 beats per minute to five or 10, and, incredibly, they take only one breath per minute.

Groundhog Day aside, not all encounters with woodchucks are pleasurable. Through the years, farmers and backyard gardeners have shared great frustrations with the animal. Its ability to wipe out a substantial plot of herbs or produce is the principal reason. It can even be a safety hazard in the fields. Farmers try to skirt burrows with their equipment, but sometimes are unable to avoid sinking into the woodchuck's hollow chambers below. The holes are detected more easily after a snowfall, when the burrow's openings stand out.

Several centuries ago, woodchucks were at home among the trees in the woodland, but learned to adapt to the wide open spaces the settlers provided by leveling the landscape for farming.

Though most wildlife did not benefit by the elimination of the wooded areas, "clearing the forest actually helped the woodchuck," says Marshall. "Their population expanded as they moved into the meadows."

In "Walden," Henry David Thoreau, frustrated by the slow disappearance of his bean field admitted, "My enemies are worms, cool days, and most of all woodchucks. The last have nibbled for me a quarter of an acre clean."

Although science has proven that the weather on Groundhog Day is not an omen of an early or late spring, many still enjoy the legend that surrounds the groundhog. And everyone but ski enthusiasts secretly hopes that Feb. 2 is a day without shadows. ABOVEGROUND

The following are some of the facilities with special events planned for Groundhog Day. All activities are free, unless otherwise noted. Some events have limited reservations. Call ahead in the event of inclement weather.

HAWKS REACH NATURE CENTER -- Little Bennett Regional Park, 23701 Frederick Rd., Clarksburg, Md. On Jan. 29 from 4 to 5, games, slides, a film and hands-on activities are part of "An After School Special" on groundhogs for ages 6 to adult. For reservations call 301/972-9458.

HERNDON COMMUNITY CENTER -- 814 Ferndale Ave., Herndon. On Feb. 1 from 9:30 to 11, a "Groundhogs Are Great!" program for toddlers (2 1/2 to 5 years) and parents will be held. A $6 fee is required for supplies. Bring scissors to class. For registration details call 703/435-6867.

HIDDEN OAKS NATURE CENTER -- Annandale Community Park, 4020 Hummer Rd., Annandale. On Feb. 2 from 2 to 4, festivities include a slide show, weather-predicting contest, crafts and a person dressed in a groundhog costume. Call 703/941-1065.

HIDDEN POND NATURE CENTER -- 8511 Greeley Blvd., Springfield. On Feb. 2 from 1 to 2, activities include stories, songs and a talk on how animals predict the weather. For reservations call 703/451-9588.

MEADOWSIDE NATURE CENTER -- 5100 Meadowside Lane, Rockville. On Feb. 1 from 3 to 4:30, "A World of a Woodchuck" allows 5- to 8-year-olds with an adult to make a woodchuck mask and visit a woodchuck hole. For reservations call 301/924-4141.

PRINCE WILLIAM FOREST PARK -- Route 619 (Joplin Rd.), Triangle, Va. On Feb. 2 from 1 to 1, children with an adult can join a ranger and look for signs of spring during a "Groundhog Day Discovery Hike." A $3 per vehicle entrance fee is good for seven days. Dress warmly and ask at the park entrance for exact location. Call 703/221-7181.

RIVERBEND NATURE CENTER -- 8814 Jeffery Rd., Great Falls. On Jan. 28 from 2:30 to 3:30, ages 5 and 6 with an adult can hear the story of Punxsutawney Phil, play shadow tag and search for groundhog burrows. For reservations call 703/759-3211.

Karen S. Saunders last wrote for Weekend about the Woodrow Wilson House.