Skunks do not hibernate. They do, however, reduce their activity levels by sleeping more. If they are not snowed in, they leave their den daily to forage. True hibernators remain asleep until the weather warms.
Sleeping more is an effective strategy to prevent winter starvation. When an animal is asleep, its metabolic rate is lower, so it requires less food.
Skunks are not particularly sociable animals, but they may make an exception in the coldest parts of winter. Several skunks huddle together in a single den for warmth. This is usually a large group of females with a single male. They use the same winter den repeatedly over the course of many years.