Skunks do not hibernate through the Winter, like most wild mammals do. They actually are fairly active in the Winter months. Skunks work hard to survive the Winter.
Unlike squirrels, they do not stockpile food for the cold months. Skunks eat extra food during the Fall, to build up a layer of fat. While this fat keeps them warm, they do still need to look for more food. Garbage cans are a common food source for skunks close to civilization, especially in the winter. They will continue to forage for food through the winter until they are snowed in.
While perfectly able to create their own dens and burrows with their claws, most skunks seek out pre-existing shelters; from other animals or humans. Skunks often take shelter in abandoned dens or under decks. Skunks live in groups, but these groups tend to be larger in the winter, and will usually huddle for warmth in their dens. Skunks will use grasses and debris to fortify their burrows against the cold.
While they do not hibernate, skunks enter at times of extreme cold or heavy snowfall, a state called torpor. Torpor is a sleep that, like hibernation, slows the metabolism and allows the skunk to survive without being active. It is not as severe as hibernation, and this lasts only short time spans; in between which the skunk must venture out for food. Skunks can allow their body temperatures to lower by about 20 degrees for short periods of time, which can give them an advantage when foraging in the cold.