One with the clockwise recommendation is he is planning a long vacation across areas that can get snow and ice at anytime from Sept on. Years ago motorcycle had their annual rally at Yellowstone and it is always the week leading into Labor day. Well they got up on Sat morning of Labor day weekend 4 inches of snow on the bikes! 2 years before that they were in Breckenridge and those that stayed over sat found snow on the bikes sunday morning! Also as others pointed it will be cooler outbound across the north and then be more comfortable in the south on the way back. Temps should have dropped some and humidity should back within live able range.