At 6 degrees outside this jacket is a short undershirt and Kurzarmtriko absolutely outrageous! Buyer of such a thin jacket, one wonders again and again, this can keep out the cold? The answer: you can! Under the jacket slightly sweated through uphill and then downhill at faster cold face and the rest of the body warm as sheltered! Is halt Gore, as I know it from all my other Gore parts here! 'M Curious whether this jacket will replace my warm winter jacket.