Sen. Dianne FeinsteinDianne Emiel FeinsteinGiffords, Demand Justice to pressure GOP senators to reject Trump judicial pick Senate confirms Trump pick labeled 'not qualified' by American Bar Association Feinstein endorses Christy Smith for Katie Hill's former House seat MORE (D-Calif.), chairwoman of Congress's inaugural committee, is estimating that the crowd at President-elect Obama's swearing-in ceremony on Tuesday will be smaller than the 5 million that was earlier predicted.

"We expect between 1 million and 2 million people," Feinstein said on MSNBC Wednesday. "Those crowd estimates have been geared down slightly. I think a lot of it depends on the actual weather of the day because people are going to have to walk long distances and stand in line and be out in the elements for at least three hours. And so if the elements are freezing or below, that's going to be very difficult."

Feinstein is the chairwoman of the Joint Congressional Committee on Inaugural Ceremonies, which handles the oath-taking ceremony.

Early predictions put the crowd at 5 million people. Those were later revised to 3 million or less.

Feinstein said that the Secret Service, the military, the FBI and the Capitol Police have been involved in security briefings about inauguration.

"And I believe that everything is being done that one can think of to see that it is a reasonably secure situation and to anticipate for what might be predicted," she said. "It's impossible to anticipate what can't be predicted. And that, of course, is the difficulty."