First season: tail of rut. crowded. short season. warm, no snow, high country all open still.
Second season: longer season, pretty late for any rut, still a few bugles to hear. probable very light snow. few chances of big storm effects to bring animals down.
Third season: too late for early rut. rare but sometimes a second-mating season for unbred cows from first rut. most bulls licking wounds in deep thickets and solitary dark timber. chance of snows limiting access to highest country, and some down migration of cows smaller bulls and calves.
Tactics: You picks your own poison. Here is my take if you are after meat: all can produce. if you are after a big bull and willing to not shoot: go first season and be there two days early to scout and get to the right place first day. do not remake my mistake first year hunting in Colorado (1986): We backpacked in two days early, set up scouted, adn then were literally run over by freaking four wheelers, roaring in on the ridgetops (not on posted or legitimate trails). It was a five mile hike out for us, an hour ride out for the ATV whimps.
Disaster first year. check on your areas, and I generally only hunt wilderness access anymore to get away from crowds. Course there are plenty of day hike wild areas that four wheelers can not get into, but know your area, cause opening day only comes once each year.
Had a similar experience on my first drop camp from an outfitter. a week later he drove his truck to pick us up where we horse packed into, course it could have snowed two feet, we were hoping.
welcome to Colorado, the edge of the midwest.
Jameister