Did a spring trip to Mammoth Mtn in April and was caught off guard. About a half foot of fresh powder and frigid temps. Top of mountain was 1 degree! Got through the two days of skiing with a bit of shivering and decided to check the Mammoth shop for something lightweight and warm.This jacket was staring me down on the rack. Only one left in a size small. Tried on and never took it off. Had the sales person clip the tags while still wearing. I'm generally a size medium, yet the small fit perfect except for a bit of snugness in the shoulders. I have a swimmers body with broad shoulders/chest and narrow waist, 5-10", 140lbs. If this was going to be used for skiing or some other active sporting activity would have passed. Otherwise fine for a warm causal jacket for those nippy days/nights. Being a relaxed fit, I'm certain the medium would have been too drapy and long.Excellent construction quality to boot.