I know, we live in Texas, but we are already getting snow and to you it may look uncomfortable to see your horse standing knee deep in snow, but horses really don't mind it. Their hooves are designed to not only withstand subzero temperatures for prolonged periods of time but they even thrive in it.
The unique vascular system within the hoof is absolutely amazing and highly adaptable to many sources of stress and adverse conditions. The limited amount of blood that reaches a horses hooves is diffused, and therefore cooled, in tiny capillaries to deliver nutrients to tissues..
However, when the horses brain gets the message that the hooves are to cold, shunts in the vascular areas of his feet open to allow the blood to move from arteries directly to the larger veins, bypassing capillaries and the chance to cool down. After the feet have warmed, the shunts close again to restore blood flow to the capillaries. A horses tail and ears have similar shunting systems as well.
Snow has tremendous healing properties for horses hooves. Many hooves after being frozen over and over have a healthier cleaner appearance.
So we need not worry to much about our horses being out in this weather as their creator has taken all precautions to tend to their needs ....So as the song goes "Let it snow, Let it snow, Let it snow." Yes even in Texas !!