Every year before the students' traditional march to the sea, Tisbury School teacher John Custer gives a lesson on Memorial Day - the holiday many people confuse with Veterans Day and associate with cookouts and sale shopping, long forgetting their own elementary school lessons on the subject.

On Wednesday Mr. Custer's social studies class was preparing for today's annual event, when they throw flowers in the water to commemorate those who died for their country. Students were seated in neat rows, their desks wearing punctured tennis balls for feet. Light poured in through large windows, illuminating the color-saturated walls papered with maps, posters, bumper stickers, political cartoons and pictures of historic locations. Each fifth-grader was clutching a blue handout entitled, "So, why do we not have school on Monday?"

One read out loud the first paragraph on the page: "This holiday honors the U.S. men and women who died in military service for their country."

The lesson had just started, but several hands stretched overhead. Mr. Custer called on a student.

"Why is there a holiday for it?" Lilly Bick asked. "Shouldn't they be remembered every day?"

Mr. Custer likes this question. "Some people do think about those people every day, but most of us don't," he said. "If you have a holiday, it's a special day. We're all expected to spend time remembering people who lost their lives for us."

On the Vineyard, Memorial Day has additional significance. It marks the beginning of the summer season, and it has done so since long before 1971, when Americans were guaranteed a long weekend with the holiday set to fall always on a Monday. A Gazette article from June 3, 1936 reads: "It was a good Memorial Day, as business reckoned, and the Vineyard did its part in entertaining the country's vacationing population."

Barring clairvoyance, business owners will never know how successful their summer will be until it's over, but that doesn't stop them reading tea leaves in the form of home rentals, ferry reservations, airport traffic, weather forecasts - and not least of all, the turnout for Memorial Day weekend.

This weekend the ferries are booked solid with car reservations, and the Steamship Authority is not taking standbys. About 225 additional SSA employees have signed on to supplement the year-round staff of about 500.

"I'm cautiously optimistic about the upcoming season," SSA general manager Wayne Lamson said. "Our bookings through the summer are up about two and a half percent from last season." Mr. Lamson hopes this could mean business is improving. "We're kind of waiting for things to turn around," he explained. "For the last four years our ridership has been level or off a little bit from previous years. Each year we hope we've reached the bottom and we'll go back to levels we have previously seen in ridership. This is a good start."

Mr. Lamson also suspects that rising gas prices could mean more Island visitors.

"That might work to our advantage with so many people living within a day's drive to the Cape and Islands," he said. "Maybe instead of going to other vacation destinations they would consider staying closer to home. We've seen that in the past - back in the seventies. There were higher gas prices and long gas lines."

The Martha's Vineyard Airport has four seasonal employees coming back to work this weekend. Airport manager Sean Flynn said he especially needs their help carrying luggage off the private jets this weekend.

"A lot of the people that are coming down will bring a lot more stuff for summer," Mr. Flynn said. "We'll see everything but the kitchen sink thrown in boxes on the airplane."

He expects the weekend will be busy.

"With the weather being what it's supposed to be, I would anticipate we'll get a lot of daytrippers on Sunday and Monday," Mr. Flynn said. "If you own your own airplane and you live in New York, a lot of people just fly in for the day, take the bus down and go shopping."

Island business owners agree that weather will dictate this summer's financial success.

"Our bookings for this year are well ahead of last year, but it might not mean anything," Twin Oaks Inn owner and Tisbury Business Association president Stephen Perlman said. "It all comes down to those last-minute reservations based on weather conditions."

Earlier this week the National Oceanic and Atmospheric Administration (NOAA) announced that a "very active hurricane season" is looming for the northeast.

"Those announcements are not wonderful," Oak Bluffs Association vice-president Renee Balter said. "When we rely so much on June through September for our annual income, it's touchy. And it doesn't help when you hear news on the radio - when you hear this is going to be a big hurricane season."

Mrs. Balter said vacation trends changed about 10 years ago.

"We've found the vacations are becoming shorter and shorter," she said. "From the mid 1900s to the end of the century, I think people planned to come for the entire summer. The mother would come with the children and then the husband would come on weekends. That has changed. Now the husbands and the wives both work and they're lucky if they can get a couple weeks off."

Tourism aside, there are several Memorial Day events planned this weekend for Islanders. The American Legion and Veterans of Foreign Wars will start their annual parade at 9:45 a.m. in Vineyard Haven along the Avenue of Flags, which will be decorated with more than 400 flags. There will be a helicopter flyover by the Massachusetts National Guard and the guest speaker will be Lt. Commander Tom Rancich. After the parade, there will be a presentation of certificates for Korean War veterans.

The Tisbury picnic will be from 12 to 4 p.m. at the Tisbury Waterworks building on Lake Tashmoo.

This afternoon at 1 p.m., before taking their long weekend, the students of Edgartown School will march to Memorial Wharf, where they will listen to the school band play, some singing, a poem and an address by World War II veteran Fred B. (Ted) Morgan Jr. before the seventh-graders throw flowers into the sea.

The Tisbury School students will parade to Owen Park at 12:30 p.m. today, including 60 music students who will make up a marching band. While the students throw their flowers, taps will be played by eighth-grader Erik Dolliver, with Willy Nevin and Gillian O'Callahan playing the echo. A ceremony and singing will follow at the flagpole.

In preparation for the march, the fifth-graders' social studies lesson continues back at the Tisbury School.

"As you know, in Iraq and Afghanistan today, the U.S. military is engaged in fighting," Mr. Custer tells the class. "Almost every day service people are wounded and killed. Memorial Day is the day to remember those people. It's not just one war, it's all the people who died."