WASHINGTON, Jan. 20 (Xinhua) -- Although U.S. presidents are elected in early November, their terms in office officially begin on Jan. 20, or Inauguration Day.

    Inauguration ceremonies are deeply rooted in tradition, but presidents throughout history have added their own unique customs.

    George Washington was inaugurated as the first president of the United States on April 30, 1789, in New York City.

    Washington's first inauguration took place at Federal Hall, where the first Congress was assembled. Washington, D.C., did not officially become the U.S. capital until 1801.

    Inauguration Day was originally held on March 4 to give electors from each state nearly four months after Election Day to cast their ballots for president and to allow for travel in an era of slow transportation.

    However, in 1933, Congress ratified the 20th Amendment, which changed Inauguration Day from March 4 to Jan. 20.

    This also changed the starting day for each congressional session from March 4 to Jan. 3.

    The 20th Amendment is often referred to as the "Lame Duck Amendment," because it shortens the time when officials who are not re-elected (known as "lame ducks") remain in office.

    Since 1937, almost every president has been inaugurated in a public ceremony on Jan. 20. One exception to this rule occurs when Jan. 20 falls on a Sunday. In this case, a brief private inauguration is conducted that day and a public ceremony is held the following day.

    The other exception occurs when a vice president is sworn in with a smaller ceremony immediately after the death, resignation or removal of a president.

    The inauguration of the president of the United States has come to be recognized by several time-honored traditions.