The wind is a bigger factor here than the temperature. I can gut out 10-12 mph headwind on the promise of tailwind coming home, but higher than that is just not pleasant.
I road from Buffalo down to Kaycee and back one time - and the afternoon heat and winds came up so fast i found myself begging for water before i could make it back to Buffalo....
Being from the Midwest - could not believe how much faster the mountain air drys you out .......