Lining doesn't really show much when unzipped, other than a strip of the inner fabric that sticks out along the placket. It's definitely warm, and the flannel inner is really, really soft of on the skin. Sometimes I throw it on without anything underneath to take my dog out at night, and honestly it just feels like wearing a flannel shirt. Word of warning, if you plan on wearing it over anything thicker than a tee you'll want to size up, shoulders are relatively narrow and the sleeves are pretty slim due to the two layers of fabric. I vaguely remember somebody posting a pic of themselves in a sized down alpaca, ended up just looking like a cropped, fitted hoodie more or less.