We visited COS in late June took the Cog up to Pikes Peak. It was about 50 degrees up there. Everyone brought jackets or hoodies to wear up there. Not me. I allowed myself to bathe in the cool, dry air. It was a little cold with the wind chill, but I wasn't sweating and it felt great. We're actually strongly considering retiring to COS. I'm told the winters there are more bearable than Denver, though I think the downslope wind would take some getting used to.