U.S. Constitution, Twentieth Amendment, Section 2
The Congress shall assemble at least once in every year, and such meeting shall begin at noon on the 3d day of January, unless they shall by law appoint a different day.
Notes
Requires Congress to assemble at least once in every year. Sets that meeting to begin at noon on the 3d day of January, unless Congress by law appoints a different day, so the required annual session has a fixed default start date that can be changed only by law.
Use as reference
Lexinter.net | U.S. Const. amend. XX, § 2 | https://laws.lexinter.net/constitution/us/amendment-20/section-2