This may be the greatest jacket ever made. Ever. You feel no wind, no water, and it's incredibly comfortable. It's lightweight and thin so it allows you to move around easily but at the same time it will definitely keep you warm in cold temperatures. Putting a fleece on underneath should keep anyone warm even when it drops below freezing. I'd say the size ran to just about what I expected, possibly slightly small for some (I'm 5'11, 168 and I got a medium and it fit perfectly) so if you're looking to wear bulky clothing underneath I'd go with a size up. I would definitely order from this site again and the free shipping took only 3 days to get to me.