Great layer to add to your gear. Ordering online, I wasn't sure whether this would replace a true sweater or make a lightweight additional layer to enable the same warmth. Overall I'd say that a traditional thick cotton sweater is warmer standing still in the wind, but obviously you can't expect to be active and wear a thick cotton sweater that doesn't wick or breathe. However, this thing packs a punch given how thin and light it is. W\en adding this layer to a long sleeve t-shirt, I was comfortable working at a grind pace in temps around -5C in a light wind. It does a great job of keeping you (and itself) dry. I bought this to take on a fall backpack mountain hunt, having been drawn to it by it's weight. This thing is definitely coming with me on the hunt as well as anywhere else I plan to explore. Also, the black with blue trim looks fantastic. As a guy with a beer belly I was expecting this trim fit shirt it to accentuate the round parts of my mid-section, but it's actually not bad when it comes to this. And messes on the shirt wipe away easily. I'm always getting snot tracks on my clothes from picking up kids and a quick wipe with baby wipe has this shirt looking new again.