The 30-foot granite statue has been cleaned. Dignitaries from around the world are in town. And the stage and 30,000 folding chairs are in place.

But it has all been in vain, as the foundation building the new Martin Luther King Jr. Memorial announced Thursday that the dedication Sunday has been postponed.

Officials seemed to have little choice with Hurricane Irene bearing down on the region.

“I’m really disappointed and hurt, really,” said Harry E. Johnson Sr., chief executive of the memorial foundation. “But the memorial is going to be there forever.”

The dedication will take place in September or October, officials said.

Johnson said the decision was made in consultation with the office of D.C. Mayor Vincent C. Gray (D), the National Park Service and others, but the final call was his.

Foundation officials had pondered shifting the ceremony, to be attended by President Obama, from morning to afternoon if the weather was poor.

But there was no way to move an event where 250,000 were expected to another location. “It’s got to happen there,” project executive architect Ed Jackson Jr. said Wednesday.

An interfaith prayer service scheduled for Saturday at the Basilica of the National Shrine of the Immaculate Conception will be the last of a week of events celebrating the opening of the memorial.

The $120 million memorial, a quarter-century in the making, was all but complete. Even the landscaping, which included the planting of trees and shrubs, was mostly finished. Only the memorial bookstore appeared to need some final touches this week.

The memorial opened to the public Monday, on a beautiful sunny day. And hundreds lined up to take a look.

Even the memorial’s master sculptor, Lei Yixin, was in town for the festivities, as well as two of King’s children.

Johnson said officials were pleased that they did a soft opening this week so that those who traveled to Washington could see the monument before having to leave.

“It is still a success because we have a memorial,” Johnson said. “We have worked so many years for this memorial, and that is a success within itself. To say that Dr. King is now on the Mall between the Jefferson and Lincoln memorial[s], you can’t ask for anything better than that. We just didn’t have a dedication; hopefully everyone will understand.”

Now the chairs must be put away and the stage removed, and the official salute for the slain civil rights leader must wait.

Gray said the city would continue to work on selecting a new date for the dedication of the King memorial.

“We’ll call and make sure that no hurricanes will come,” he said. “We’ll put this request in right away.”

Staff writer Hamil R. Harris contributed to this report.