My summer homebase is at 8500 ft in the Colorado mountains. I never leave here to head south until the end of Oct. We do ocassionally get an early winter storm come through in Oct and drop some snow, but its gone the next day as soon as the sun comes out. Oct will be 90% blue sky and sunshine, just keep tabs on the forecast and sit for a day if any major storm crosses your path. Usually those early winter storms in Oct only last a day and only impact the high passes at 10,000 ft or higher. Some Oct days I'm out in T shirt & shorts here at 8500 ft, but Wolf Creek Pass, just 20 miles up the road at over 10,000 ft got 10 inches of snow.