In Sept in Alabama when I bought mine it was upper 90's and in the 100's with 75-100% humidity some. I rode, it was miserable, BUT NOT from the engine heat and it did not overheat, fan definitely came on more often than it does right now in 30-40F weather.
Yes the foot well was warm to the touch but only a few degrees warmer than ambient air temp you could leave your bare leg against it and it not be uncomfortable.
The back should be warm in warm weather, you are enclosed it a bed area, but there is a good distance and a heat shield between the seats and the muffler.
Def prefer late fall winter and early spring riding.