I ride in temperatures that range from mid 30's to the low 60's in the same ride. This jacket keeps me warm with the sleeves on and keeps me cool when I zip off the sleeves and unzip the front. You can also partially unzip the sleeves around the armpit for more ventilation when your body temperature gets up. Perfect for light rain too! I usually a medium but I have wide shoulders. I ordered the large and it is perfect in the shoulders and i little loose in the body but not too loose.