Even if a winner is declared in the Presidential Election in the coming weeks, that doesn’t mean it’s official. Here is the timeline:

• ASAP, no later than December 14, 2020: Governors’ Ascertainment of Results. The executive of each state is required to certify his/her ascertainment of the state’s election results to the Archivist of the United States “as soon as practicable,” but no later than the date the Electoral College meets. Date set by federal law. See 3 U.S.C. § 6.
• December 8: State “Safe Harbor” Deadline. This is the deadline for states to resolve disputes concerning the appointment of electors (pursuant to laws enacted before Election Day) in order to have those appointments treated as “conclusive” by Congress. Date set by federal law. See 3 U.S.C. § 5.
• December 14: Meeting of Electoral College. Electors meet in their respective states on the same day to cast their votes. Date set by federal law (but required by the Constitution to be the same for all states). See 3 U.S.C. § 7; U.S. Const. art. II, § 1, cl. 4. Receipt of Certificates of Electoral Votes This is the last day for certificates of electoral votes to be received by the Senate and Archivist. Date set by federal law. See 3 U.S.C. §§ 12-13.
• January 3: New Congress Sworn In. This is the day on which all newly elected Members of Congress are sworn into office. Date set by Constitution. See U.S. Const. amend. XX, § 1.
• January 6: Joint Session of Congress. Congress opens electoral certificates from the states, considers any objections and resolves them under federal law, and counts electoral votes. Date set by federal law. See 3 U.S.C. § 15.
• January 20: End of Current Presidential Term. The current presidential term ends at noon on January 20th. Date set by Constitution. See U.S. Const. amend XX, § 1.