It’s been called the biggest event on the Vineyard social calendar, and the Possible Dreams Auction organizers found how to count just how big it had grown when a storm hovered over the lawns of Edgartown’s Harborside Inn on the first Monday in August last year.

They could count more than 600 phone calls they made (even while the sun shone) to tell donors and ticket holders the celebrity fundraiser would be rain-delayed for the first time in its history. They could count hundreds fewer people there bidding the next day, their absence due to plane and ferry reservations or work on Tuesday. No one could account for the loss of the late Art Buchwald, who for decades had conjured an ever-bigger crowd and cajoled more bucks out of them.

At the end, though, there were hundreds of thousands of dollars less for Martha’s Vineyard Community Services to count on the rest of the year (down from over $800,000 to about $560,000).

“I really know how much this event means to the agency and the many people who depend on it, so it’s always a stressful day,” said development director Jan Hatchard. “Last year was just exceptional.”

So a strategic rethink began almost immediately. The 30th annual Possible Dreams Auction will be different.

They dropped the raffle and the online auction and slimmed the list from fifty-some “dreams” to thirty-some. They recruited some dreams from a new generation of celebrities, and will stage a high-price dinner to honor the first generation of donors. They decided it was too soon to anoint a new celebrity auctioneer but about time to move the waterside event so it could be held rain or shine. This year’s auction will be under a tent at Outerland, the night club formerly the Hot Tin Roof at the Martha’s Vineyard Airport.

Whatever the weather, the auction will take place amid other variables: It’s a national election year, which previously has seen the auction’s fundraising slip in the politicians’ wake. The slumping economy is stretching from Main street to Wall street. Proliferating galas are crowding a season already shortened by demographic changes; fewer people come to the Island for the whole summer any more. Even the Hollywood writers’ strike is having an impact, with filming schedules delayed such that Possible Dreams stalwarts like Harold Ramis cannot be at the auction this year.

“It’s heartening that some of the other events have done well,” Mrs. Hatchard said. Anecdotal reports suggest the Vineyard fundraising circuit may be holding up better than the Hamptons, where charities are reporting financial fallout. “Still we’re very cautious this year,” she said. “Some people are out four nights a week at different events and could be out seven,” Mrs. Hatchard said. “And it’s a difficult financial period, and it’s one we haven’t seen in a long time.”

The Possible Dreams Auction, which has spawned many imitators, began in 1979 with dreams you could buy for $10 (these days, even admission is $25). It raised less than $2,000 that first year, but the rules were set: bid for experiences you could not buy, anywhere else, and all with a Vineyard connection.

The formula has proven phenomenally successful. In just a few years, revenue had increased tenfold, to almost $20,000. When it poured rain in 1984, a rubber-soled Mr. Buchwald tempted electrocution to stay at the microphone and wrangle $24,000 from huddling patrons.

The next year clouds forced the crowd into a humid gymnasium, yet the auction raised more than $30,000. The next year it hit $40,000, then $70,000 and so on, in a mostly steady increase to its peak two years ago. The size of the audience had grown too, so that it would no longer fit in the gym of the Martha’s Vineyard Boys’ and Girls’ Club. “We have had over 1,000 before,” said 20-year committee member Jim Pringle, noting that without any suitable rain location last year, organizers opted for a rain date. “The rain postponement cost us probably quite a bit of money,” he said.

“It was such a massive undertaking to move it at the last minute,” said Judy McCarthy, in her 25th year on the auction committee. “To get 100 volunteers to leave two days free, never mind all the chairs, the food . . .”

After that, she said, “everyone was torn. We all wanted to stay [at the Harborside] and we all knew we needed to try something different.”

Mrs. Hatchard said Harborside Inn manager Joe Badot joined the venue search.

“He helped us realize we could not tent the garden there; it takes three days, trucks can’t get near ... and people paying to vacation there would lose their view,” she said. “We explored it every way we could.”

“So we investigated various sites around the Island,” said Mr. Pringle. “It had to have power for electricity, ease of access, considerations as to the food at the auction . . .”

Many longtime volunteers were still against a move away from the Harborside Inn. “It was such a difficult decision,” Ms. McCarthy said, “I think even as people were making it, most had gone in [to the presentation by a venue subcommittee] expecting they couldn’t possibly go with the change.”

But they did. “As different needs have arisen or abated, Community Services has been very responsive,” Ms. McCarthy said. “Its strength is how flexible it is to meet community needs. So we felt like we were following in those footsteps, being flexible.”

Outerland won over the dreams committee, which has been meeting every two weeks since November last year.

Parking is somewhat complicated by the night club’s proximity to the airport. Still, they see it as an improvement on trying to get into downtown Edgartown, an exercise that clogged roads and caused accidents.

Huge tents mean more expenses, but Mr. Pringle said “pretty serious money” from corporate underwriters Comcast and American Express mean the cost to community services won’t be much higher.

“We can put 1,100 people in there, with some people standing — there’ll be 890 chairs,” Mr. Pringle said. “There will be parking at the high school and a free shuttle, and parking at airport but it costs.”

Mrs. Hatchard recused herself from the decision to move. “In my head, I had already decided this rain date could never happen again,” she explained. “I didn’t want the risk of having to postpone. . . . the calendar is very busy, and I wouldn’t want to step on someone else’s day.”

The decision to change venues went hand-in-hand with the overall rethink, Ms. McCarthy said: “Like, it’ll take a little while to work out what it will be like without Art and how we’ll handle that. We didn’t want to go right to having another celebrity auctioneer. We need time for a transition.”

The transition to a new generation is already under way. “We have younger people on the committee now and it’s kind of a different focus,” Mr. Pringle said. “A lot of people they are talking about for dreams, I have no idea who they are.”

The test comes August 4. After making much less than expected last year, Community Services tried to make it up, streamlining their own services even as their costs increased. “Our staff and clients are suffering,” Mrs. Hatchard conceded.

“Now as it passes to a new generation, we’ll begin to see how that shakes out,” she said. “It’s one evening even that can make such a difference on this Island.”