In the desert, where I usually ride, day temps range from 40-60 degrees in the winter. I would definitely over heat in this jersey; the fabric is heavier than I thought it would be. I did try it on and the large fit well, in a semi-fitted way. I'm 6'1", 165',41"chest, 34"waist, 36"sleeve. BTW, BC handled the return in their usual expeditious manner.