Must a voter declare a party affiliation before election day in Colorado?

In Colorado, voters must declare a party affiliation to participate in that party's primary elections, but they can change their affiliation up to eight days before the election. However, for the general election, there is no requirement to declare a party affiliation; voters can choose to vote for candidates from any party. Registration can be done online, by mail, or in person, and Colorado also offers same-day registration.