Another suggested (and highly recommended) time is the weeks after Labor Day weekend. Hotel rates usually come down, traffic has dropped while kids are in school, temperatures have moderated, and monsoon weather patterns are usually over. I prefer the last two weeks of September myself. If you want to see fall color, the Aspen begin to turn sooner in the northern part of the state and don't peak in southern Colorado until the last week of September or first week of October. If you travel through Rocky Mountain National Park there'll be dozens of bulls bugling in Estes Park and the the Park itself. If you've never experience the elk rut before, you ought to time your trip to see it. Best time for this would be Sept. 20th to about Oct. 10th. Yes, you can hit some snow during that time, but you can get snow or heavy rains all other times as well. Don't fear Colorado weather. Bring your riding gear and include polypropylene underwear. We wore our leather during the August ride that Billnourse mentioned and I wished I had left them at home. Good rain gear is a must though!! You'll use it to break wind and help insulate your regular riding gear when you ride about 12,000' (which you'll do more than once a day). During the day you'll be putting your rain gear on and taking it off more than once. If you do know when you're coming this way and drop down into the southern part of the the state you should give me a call. We might have a room and hot shower available for you.

 

Appreciate the invite! Pretty sure we will do sometime early to mid summer simply because of both mine and my wifes ability to take off a little longer during that time period. I have always done the Smoky's around Labor Day and the weather is always near perfect but it always is only during the long weekend because of work being busy that time of year. Between trying to figure mine, my wife's, and hopefully my son's schedule it will take a while to set a certain date.

 

July and August have always worked for me. You never know when it will rain but when it does you don't want it to be cold. Have a nice trip.

Ouray to Silverton is a nice ride..

 

Very late update in OP

 

I was all through the west last year. Usually had the electrics on in the morning and down to a T-shirt and vest after lunch. The Beartooth was closed for a few days in August due to fresh snow. Take gear like you will be cold and wet; and you will be fine. If you don't have them; invest in a set of handle grip heaters. You will wonder how you ever rode without them.

When you are above 6,000 ft, and especially in the morning; even on Sunny days, , if you see off colour pavement, assume it is black ice.

 

That is a very good tip about the black ice! Thanks!

 

I did early August when I went. The advice about rain gear is good. I hit rain leaving RMNP all the way to Dillon which was my destination that day. Was cold in the mountains, wet from the rain. I stopped in Winter Park to warm up and grab some food, was nice by the fireplace they had running there in August that day. Total bucket list trip it was awesome. It rained one or two more times that trip but thankfully not while I was riding.