Figured I'd weigh in on this one as well. I only wear Utilikilts, however last winter I only owned two Originals which are lightweight twill. I got through pretty much the whole winter wearing them and only a couple times resorted to wearing long johns with the kilt (a bit of a Seattle grunge look, so to speak). However, this year I have two Workman's (cotton duck) in my wardrobe and I haven't worn anything but tall woolen boot socks a couple days when the temps were routinely in the the teens. Like Kilted Hiker and a few others have mentioned - I don't seem to feel too cold on my legs as long as I've dressed my body core warmly. Hat, gloves, and maybe a couple layers under my M1 jacket and I'm set. And if it gets really booger-freezin' cold then I can always break out my airforce extreme cold weather flying man's jacket which is just like my M1 but with a button over front and a fuzzy zip up parka hood. Now that's a warm jacket. I get the "Aren't you cold?" comments all the time and I simply reply "Nope," or to those I know, "My ancestors were Highlanders so I'm pretty sure resistance to cold is in my blood."