Hurricane Irene forced thousands of people across the country to scrap plans to visit the District this weekend for the planned dedication of the $120 million Martin Luther King Jr. Memorial, thwarting an expected boost to the city’s tourism industry.

About 90 percent of the city’s 29,000 hotel rooms were booked, far higher than the 60 percent occupancy rate typical of a late-August weekend, said Elliott Ferguson, president and chief executive of Destination DC, the city’s tourism and convention organization. “Traditionally, this is a slow period for us,” Ferguson said. The hurricane “is a game-changer for us in terms of the economy.”

The memorial foundation, which had planned a star-studded dedication for Sunday that was to include President Obama, announced Thursday that the dedication will instead be held in September or October. Cancellations of other events that were scheduled for Saturday quickly followed: a local march for District voting rights, a nationally sponsored “jobs and justice” march, and a number of official galas and private parties.

But Ferguson and others were heartened that the dedication was postponed, not canceled. The revenue, they say, will just come a different weekend. Organizers of chartered bus trips to the event said hotels and bus companies were being cooperative with cancellations and refunds.

Restaurants were also hoping to see a bump in revenue from the influx of visitors, but the weekend may not be a bust, said Lynne Breaux, president of the Restaurant Association Metropolitan Washington.

With Washingtonians abandoning traditional trips to the shore during the last days of summer, restaurants could be the place to be, Breaux said. “They’ll stay in town. That will fill the gap,” she said.

City and tourism officials said they did not have a dollar figure on the lost revenue.

Destination DC is working with the memorial foundation to find a new date for the dedication, but Destination DC also will promote Labor Day weekend as an ideal time for rebookings, Ferguson said.

In the District, 16 hotels participated in a package deal that gave hotel guests tickets to the dedication, according to Robin McClain, director of communications for Destination DC. About 10,000 out of the 125,000 tickets available for the dedication were part of package deals, McClain said.

Bruce Lightner, founder of the Raleigh King Committee in North Carolina, said Marriott was allowing his group of 236 to rebook for the dedication’s rescheduled date. “Initially, everybody in my group was disappointed,” he said. “But I’ve only talked to two that say they can’t go in September or October.”

Lightner said he has been planning trips for years to honor King, leading an annual, multi-day tour of Atlanta, Memphis and the Alabama cities of Birmingham, Montgomery and Tuskegee. For this weekend, Lightner had booked four buses and scheduled tours of the White House, the Lincoln Memorial and other sites for Saturday. “It was a good mix of senior citizens, we had some college students, we had some high school students,” he said.

He recalled being a young man in 1963. “When I was in high school, my parents didn’t know, but I snuck out and hitchhiked to the March on Washington.”

Other tour groups did not book hotel rooms but were planning on dining and spending money on souvenirs.

In Evansville, Ind., Sondra Matthews, founder of the African American Museum there, was surprised that none of the 47 other people who paid $125 each for the 13-hour bus trip she planned had called to ask for refunds. “Everybody’s still on,” she said. “We’re just waiting on the date.”

James Ivery, a minister in Jefferson County, Ga., was getting the same response from the more than 100 people who were going to travel overnight Saturday to attend the dedication. “The majority of people, more than half, are saying, ‘Hold onto my money, and wait for the date,’ ” said Ivery, president of the county’s chapter of the Southern Christian Leadership Conference. “People weren’t disappointed, because they know you can’t control the weather.”

They’ll be in the District in the fall. “The only way I can miss this is if I’m in my grave or if I’m in the hospital,” Ivery, 59, said.