When is inauguration day not held on January 20?
Since the ratification of the 20th Amendment to the U.S. Constitution in 1933, U.S. presidential and vice-presidential terms always begin/end on the 20th of January. However, when that day has fallen on a Sunday, the President took the Oath of Office privately on the 20th then again publicly on the 21st. Inauguration Day has fallen on a Sunday three times since 1933: in 1957 (Pres. Eisenhower's second inauguration), in 1985 (Pres. Reagan's second inauguration) and in 2013 (Pres. Obama's second inauguration).