Im 54 133lbs, I opted for the size Medium (I usually opt for a Small in jackets/hoodies/tops), but after reading a few reviews I sized up....and Im glad I did. Its snug, but not uncomfortably tight. Not very heavy, but its very warm (the lining seems to be made of cotton.) Seems to be made of great quality and feels really soft. Will purchase another one, in a periwinkle blue color. Dont hesitate, just buy!