The 20th Amendment ends the president's and vice president's terms of office on January 20 at noon.
Laws passed by Congress state that “the electors of President and Vice President of each State shall meet and give their votes on the first Monday after the second Wednesday in December next following their appointment at such place in each State as the legislature of such State shall direct.” This year, that day is December 14, 2020.
States must send their electoral votes to Congress by December 23, 2020. Electoral votes are counted in a joint session of the new Congress at 1 p.m. on January 6. If there is no electoral decision, the House selects the next president and the Senate selects the next vice president, by January 20.
THere won’t be a House on January 20 without a clean election.