I followed their sizing chart, called the company for confirmation and then ordered the wide width, thinking that I would fill the space with a liner and a THICK wool sock. (My feet get cold easily when I am out all day <img src="/forums/images/graemlins/frown.gif" alt="" /> ) I really did not need the extra space as my feet stay warm in just a pair of smart wool socks with the mukluks. Yes, they sell waterproofing spray which is effective in cold weather but I would not try to wear mukluks in slushy snow. They really are only for below freezing, and preferably teens or lower, temps.