I've been wearing this during evening hikes and cooler weather. This hoody did a great job of breathing, even with a pack on, and kept me surprisingly warm. It was basically the only layer I needed for a recent climb of Mt. Baker (save a t-shirt and puffy for when we stopped moving). It maxed out at being "too warm to wear" when temps hit 80 degrees - which is pretty fair. Looking forward to adding it to the winter lineup. I am 5'7", 140 lbs, and ordered a medium. It's larger in the chest area than I need (though not overly so), but the overall length and shoulder room were just right. The drawcord hem did the trick to keep it snug.