The memorial on the National Mall opened to the public this week, but the dedication ceremony, including a speech by President Barack Obama, was scheduled for Sunday.
Organizers were expecting a quarter-million people. With Irene bearing down on the East Coast, they decided to call it off.
"I don't see it as negative that the dedication is postponed. I see it as, we're here to do the work that still must be done to continue what Martin Luther King Jr. represented," Martin Luther King IIIl.
Crews rushed to disassemble the grandstands that had been set up for the dedication on Friday. So far, there's no word on when it will be rescheduled.
Alpha Phi Alpha fraternity brothers, meanwhile, celebrated the results of their perseverance despite the weather.
The fraternity brothers, clad in either black suits or gold blazers, went ahead with their own preplanned dedication on a smaller stage at the same site on Friday
Large TV screens beamed the speeches, prayers and entertainment to an audience of hundreds - and to thousands of empty chairs.
King was a member of the fraternity, along with many prominent African-Americans. Alpha Phi Alpha members worked to get the memorial approved, and to raise money for the $120 million monument. The Associated Press contributed to this report.