C.R.S. § 31-10-601

At all elections held under this article, the polls shall be opened at 7 a.m. and remain open until 7 p.m. of the same day. If a full set of judges of election do not attend at the hour of 7 a.m., an alternate election judge shall be appointed as provided in section 31-10-405 . The polls shall be opened if a majority of judges are present, even though the alternate judge has not arrived. Every person, otherwise qualified to vote, who is standing in line waiting to vote at 7 p.m. shall be permitted to vote.