I like later in the season if given a choice. If you are in a couple of miles pressure probably will not be an issue. My work schedule usually decides when I go. Being from Michigan, hunting the early season in Colorado always seams to hot to be hunting. I don't mind having snow on the ground and cool weather.
In the areas I have hunted September temps typically have been lows at night in the 20's or 30's and day highs in 50's or 60's. Snow rarely lasts more than a half of a day after it stops falling. There are always exceptions during the course of any season, both ways - very hot or very cold. I remember one year in the mid 1990's I was out the third week and it was very dry and in the 80's and 90's every day, fun trip but poor hunting. I have also been snowed on the first week of season so plan on cold no matter when you go.
Back when I first started going to Colorado (1985ish) the bow season started in August - it was a good thing because I was in grad school, so I would not have been able to go in September. I remember it being just plain hot then, even at 10,000 feet.
I guess what I am saying is go when you can. The weather will do what it is going to do, it may be good or bad either week - you will not know until you are there.