It was a beautiful Friday afternoon in the Hudson Valley, 70 degrees in October and not a cloud in the sky: perfect weather for apple picking.

All over the 175 acres of Barton Orchards, in Poughquag, a town about 20 miles east of Beacon, moms and dads in T-shirts were pulling apple-laden carts down the orchard avenues, or staging photos of their children gleefully toddling around a pumpkin patch. A small crowd awaited a pig race, some of them clutching little checkered flags they had purchased for a dollar.

But Peter Barton, the farm’s owner, couldn’t help but be preoccupied with the forecast. The weekend outlook had recently shifted from two dry days to just one. Steady showers were predicted for Sunday.

“That’ll be eight weekends in a row,” Mr. Barton said. “It’s absolutely, absolutely unheard-of.”

According to Mr. Barton, this has been, without question, the most miserable fall tourism season since he converted the family apple orchard to a pick-your-own outfit in the 1990s. Over the decades, Mr. Barton said, he has spent “millions upon millions” building the venture up, adding a corn maze, an enormous playground, a petting zoo, and a tap room that sells hard cider and local microbrews. In recent years, he said, the property has drawn more than 10,000 visitors on peak weekends.

For Barton Orchards, which like many apple-picking farms makes most of its annual income from tourists filling bags with Galas, McIntoshes and Honeycrisps during two months in the autumn, the recent spate of wet weather has been nothing short of disastrous.

Nearly 10 inches of rain have fallen on the region in September and October, according to the National Oceanic and Atmospheric Administration, 25 percent above normal. But those numbers don’t capture the true extent of the bad luck: The wettest days have disproportionately fallen on weekends, when pick-your-own farms receive most of their visitors. Commercial orchard crews work rain or shine, and this year’s downpours haven’t kept them from getting the apples off the trees. The general public, though, prefers to pick apples in nice weather.

It all started the weekend after Labor Day — the agritourism equivalent of Black Friday — when almost an inch of rain fell across the Hudson Valley between Friday and Sunday. Wet weather has struck on at least one day of each weekend since, leaving orchards sodden and turning parking lots into mud pits. Mr. Barton maintains that he’s lost at least 30 percent of his business this season to the incessant rainfall. Other u-pick orchard owners estimated that their fall revenue has decreased by a quarter to as much as a half.

According to Cynthia Haskins, the president and chief executive of the New York State Apple Growers Association, the self-pick orchard grew in popularity in the late 1990s, after deteriorating wholesale prices caused many small farms in New York State — the nation’s second-largest apple producer, behind Washington — to either leave the apple business entirely or find other avenues for marketing their produce. For those located within an easy drive of New York City, on-farm retail seemed like a natural fit.

“I’ve been farming since 1972, and this is the roughest fall I’ve ever seen,” said Bob Stuart, who converted his 35-acre apple farm in Granite Springs, N.Y., to pick-your-own in 1999, and now relies entirely on fall crowds for the farm’s annual income. This year, hay rides have been stymied by tractor wheels sticking in the mud, and he didn’t even bother to cut his corn maze; it would have been a soggy mess. “People aren’t coming out,” Mr. Stuart said. “You’ve got seven weekends to make it in, and if you lost half of your days, you’re out of luck.”

It’s the same story at Apple Dave’s, in Warwick, N.Y., where the owner, Peter Hull, said the bad weather has cut autumn visits to the farm by half. Mr. Hull’s father, Dave, switched from selling apples wholesale to a pick-your-own model in 1974, when the farm’s storehouse burned to the ground with the year’s entire crop inside. “The next year he couldn’t pay pickers or packers or truckers,” Mr. Hull recalled, “so he sat out there with paper bags from Shop Rite and said, ‘Come pick your own.’”

To help diversify the farm and move away from its reliance on the u-pick business, Mr. Hull built a distillery on the site, but it hasn’t served as much of a buffer this fall. On a nice weekend day, Apple Dave’s might see 3,000 visitors. The distillery can accommodate only 50 to 70 people.

As of the last week of October, many of his trees were still loaded with apples, destined to drop to the ground and rot. Should climate change lead to more rain-drenched autumns like this one, Mr. Hull doesn’t see any obvious ways for a retail apple orchard like his to adapt. “I’m wondering if we should all be getting more religious,” he said.

In the wake of this year’s weather woes, some orchards have been getting creative to try to recover lost sales. At Pennings Orchard, in Warwick, N.Y., they’ve hauled in giant spotlights and opened the orchards to apple picking and hayrides on weeknights.

Normally the apple picking season closes at the end of October, but with so much fruit left on the trees this year, some farms are planning to extend into November, hoping the weather will stay warm enough to preserve the picking for another week or two. Most, however, have resigned themselves to the idea that there’s no chance of making up for all the income they’ve lost. For some, that will mean taking on new debt, or delaying repairs, or putting off equipment purchases for another year.

Harvest Moon Orchard, in North Salem, N.Y., fills September and October weekends with “fall festivals” that feature a doughnut trailer, cider slushies, hay rides and live music. Kristina Jahaly, the farm’s general manager, said that festival days draw as many as 5,000 visitors. This year, rain has canceled eight out of the 16 events.

Luckily, she said, the farm is in its third year of offering a “festival of lights” — a ticketed, walk-through “light experience” taking place during the winter holidays. “That’s another thing that we’ll rely on to prop up the business,” Ms. Jahaly said.

Back at Barton Orchards, Mr. Barton is already looking to future seasons and is pressing ahead with the construction of a mammoth covered pavilion where he plans to hold live music events. It is a major investment, but one that he hopes will help the farm operate rain or shine.

“Picking apples is an amazing family event, and we’re still on the low-end, cost-wise, for entertainment,” he said. “We have a business that’s almost recession-proof. Unfortunately, it’s not weatherproof.”