With few exceptions, 1983 has been the year for wet weekends.

Seventeen out of this year's 21 weekends have been marred by some form of precipitation, with April and May holding perfect soggy-weekend records. So far this year, Washington-area residents have endured six inches of rain more than "normal" (based on 30-year averages), including 1 1/2 inches more than normal in May alone, weather officials said yesterday.

The holiday weekend received three-fourths of an inch of rain, according to forecasters, who called for more showers tonight lingering into Wednesday. The outlook for next Saturday? No surprise: more showers.

Such a deluge has dashed the hopes of weekend gardeners and sailors, delayed pool openings and, this past weekend, put a damper on holiday barbecues. The emotional spillover is obvious.

"People who are already depressed tend to be more depressed by rain," says Chevy Chase psychiatrist Henry Segal. "The weather becomes an excuse to climb in bed and hole up." A couple of his patients are particularly sensitive to the lower barometric pressure that accompanies rain, he said, and suffer secondary depressions due to acute sinus problems.

Commercial spirits also have been dampened. "Forty-five out of the last 60 days, the river was too high for us to let people out," said Ray Fletcher, fifth-generation owner of Fletcher's Boat House on the Potomac in Northwest Washington. Rain has cut this season's business by one-third, he said.

"Any time it's above five feet at Little Falls, one and one-fourth miles north of us, we don't rent canoes or rowboats."

Yesterday, Fletcher rented 40 rowboats to stalwarts determined to ignore threatening skies. But his bike rentals and bait and tackle business are hurting.

"I've seen a lot of bad springs, but this is one of the worst," he said.

The water slide at Wild World theme park in Largo had some takers despite the intermittent rain yesterday. But the park has had 12 percent fewer visitors thus far this season because of what marketing director Thomas Osiecki calls "duck weather."

The flora are not doing well either. "We're seeing more smutty mold and rust," said Alfred Millard, manager of Behnke Nurseries Co. in Beltsville. Fungus is turning bluegrass yellowish brown, he said.

Wetness, combined with a late frost May 17, has been murder on herbs, Millard said. "There are more plant diseases, more fungus due to humidity and cooler temperatures, more black spot on roses," he said. And lawns are afflicted with diseases that don't usually crop up until late summer, he added.

Rainy weekends have hurt the store's business as gardeners have waited to plant, Millard said.

Similarly, the swimming pool servicing business is running two weeks behind, according to Kirk Russell, service manager of Waterworks Inc. of College Park.

"You can't do any concrete work in this weather. In-ground vinyl liners are actually floating shapeless in some pools," Russell said. "We opened three pools Saturday in the driving rain."

The outlook for June is cool and rainy, according to Jim Travers, forecaster for the National Weather Service. The wet weekend cycle will shift eventually, he said; it's not necessarily a seven-day pattern. But he declined to predict when the next entirely sunny weekend may occur.

The current stretch of wet weather began after a dry spell in January, Travers said. Air currents 20,000 feet above the earth's surface have come from several directions, picking up moisture from the Gulf of Mexico and the Great Lakes and dropping it along the East Coast.

Right now, the Washington area is in a transitional period, when winter-type storm systems are not uncommon. For example, this Memorial Day weekend was washed out by a low-pressure system and cold front that moved from Canada south of Chicago, storming into town Sunday.

One storm system affects another, Travers continued. The peculiar weather conditions experienced around the country in recent months--record rains on the California coast and in the Rockies, floods in the Mississippi delta, an unusually mild winter in the Midwest and Northeast and Washington's freak two-foot snowfall in February--were due to "interconnected" storm systems, Travers said.

Can he put it in simpler terms? "On weekends it rains and during the week we have nice weather."

You don't say.