Very comfortable, but not necessarily warm
This is one of the most comfortable pair of socks I've ever owned. However I don't know that I'd call them 'cold-weather' gear. Last fall I comfortably wore them down to maybe 40 F or 45 F, but below that I needed something a little heavier. It could just be me. Nonetheless, I plan on ordering more. I don't even like to take them off when I get home from riding.