ya ive used knee warmers with them at about the same temps, they work pretty good and i find them the best combo of wind protection/warmth/breathabilty.

I had to break down and get some waterproof ones for days its pouring though, with the whirlwind ones the water was going in the spandex back, running down my legs, and filling up my goretex socks Definatly my favorite tights though.