Originally Posted by elcruxio

Typically XC ski shoes have much better insulation (neoprene etc) than winter cycling shoes. For some reason cycling shoes are trying to be too much like ordinary shoes to be all that useful. I can only wear very thin socks in my ski shoes and I've never had frozen toes even in -30C.

There's also a smaller slab of heat sucking steel in ski shoes and it's typically more removed from the foot.

And perhaps most importantly, you use your foot when skiing keeping the blood pumping. In cycling the foot is pretty much static.