Colorado has no presidential primary. All parties choose delegates to national conventions by caucus. On April 30, the Colorado House passed HB 1376 on 2nd reading. It moves the caucus date from March, to February 5.
Most states with caucuses don’t try to tell parties when to hold their caucuses, but Colorado does.
From my reading of H.B. 1376, it would leave the default caucus date as the third Tuesday in March, but, in presidential election years, “a political party may, by decision of its state central committee, hold its precinct caucuses on the first Tuesday in February.”
So in midterm years, caucuses must be held on the 3rd Tuesday in March, but in presidential years, parties have a choice between the 3rd Tuesday in March or the 1st Tuesday in February.