This is what the ASPCA recommends- “Never shave your dog down to the skin in winter, as a longer coat will provide more warmth. When you bathe your dog in the colder months, be sure to completely dry him before taking him out for a walk. Own a short-haired breed? Consider getting him a coat or sweater with a high collar or turtleneck with coverage from the base of the tail to the belly. For many dogs, this is regulation winter wear.”
The only time I would recommend shaving a pet in the winter is if they are kept indoors at all times (in a climate controlled environment like the house – not a shed), and or they are extremely matted. If you are on a tight budget after the holidays get a bath and brush for your pet and stretch your groom a little longer. Don’t forget to brush at home too. If your pet is normally in the house then they need to stay in during the winter. They are not acclimated to colder temps and therefore have not had time to develop a winter coat to help protect them from the elements outside. If they are not in the house, consider bringing them in. We have seen record breaking cold temps this year in Texas and just like we are not used to it, our pets are not either.