from 1793-1933, Inauguration day was March 4th. The 20th Amendment to the Constitution of the United States changed Inauguration Day to the 20th of January.
I quote from Section 1 of that amendment:
“Section 1. The terms of the President and Vice President shall end at noon on the 20th day of January, and the terms of Senators and Representatives at noon on the 3d day of January, of the years in which such terms would have ended if this article had not been ratified; and the terms of their successors shall then begin.”
Chanukah and Purim also occur on definite days, though that is not to be found in the Constitution.