The Smithsonian Institution, "The Castle," the building on the National Mall that is home to the Smithsonian's administration. (ASSOCIATED PRESS)

Visitors to the Smithsonian Institution and the National Archives will notice changes to summer hours and exhibitions as of May. The Smithsonian will begin closing certain galleries on a rolling basis come May 1 because of across-the-board budget cuts known as sequestration. The National Archives, which held extended summer hours in the past, will maintain its regular schedule of 10 a.m. to 5:30 p.m.

The leaders of the Smithsonian, the National Park Service and the National Archives and Records Administration testified before Congress on Tuesday about the effects of the budget cuts. The House Committee on Oversight and Government Reform questioned the directors about how their agencies are handling the approximately 5 percent reduction and how it might affect the public.

Smithsonian Secretary G. Wayne Clough told Congress that the Smithsonian prepared for $42 million in cuts last year by restricting travel and training, instituting a hiring freeze and curbing the maintenance of collections.

“The goal is to keep our museums open,” Clough emphasized, while noting that the reductions will “force hard decisions in 2014” if they remain permanent.

The Smithsonian does not plan to close museums but will close galleries or exhibitions on various days. In written testimony, an instance of a closure was described thus: “Visitors may find a sign saying that the 3rd floor galleries are closed to the public that day.” Smithsonian museums are open every day of the year except Dec. 25.

People wait in line to get a rare glimpse of the Emancipation Proclamation at the National Archives on its 150th anniversary. (Katherine Frey/THE WASHINGTON POST)

Clough noted that the cuts could have long-term effects on preservation and planned maintenance projects at the National Air and Space Museum and the National Zoo. He also indicated that a multimillion-dollar decrease in funding to the National Museum of African American History and Culture could delay its scheduled opening in 2015 and affect staff hiring.

David Ferriero, archivist of the United States, indicated that the National Archives began preparing for $19.7 million in budget cuts in 2011 with an agency-wide hiring freeze and a 41 percent reduction in travel budgets.

Because of reductions, the National Archives locations in the District and in College Park will not have extended summer hours. In past years, the archives had extended public hours from 10 a.m. until 7 p.m. seven days a week until Labor Day. The building will close at 5:30 p.m., while the public research rooms at both facilities will operate 9 a.m. to 5 p.m., Monday through Saturday.