Honey bees do not hibernate. According to Wikipedia, “Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food is short, by tapping energy reserves (body fat) at a slow rate.”
Many insects hibernate, especially in the larval or pupal stages, and a few hibernate in the adult stage. Queen bumble bees, for example, hibernate all by themselves in the ground for approximately five months.
However, honey bees remain “awake” all winter, during which time they eat and keep the hive warm. The winter activities—especially heating the hive—require vast amounts of food energy and are the reason that honey bees store so much nectar.
Evidence that honey bees do not hibernate is plentiful. For example, if you knock gently on the side of your hive during the winter, you will hear a great roar of agitation. This is because the bees are awake and perceiving danger. Also, if you check your hive frequently you will often see feces in the snow or notice dead bees on the landing board. This is because, on warmer days, the bees seize the opportunity to eliminate body waste and tidy up the hive by removing the dead bodies.
Another piece of evidence is that the hive keeps getting lighter all winter long. If you lift the back edge of the hive an inch or so, you will notice a big difference in weight between early fall and late spring—proof that the bees are eating the stored honey and turning it into heat.
A warm pre-spring day with temperatures in the 60s will bring them out by the thousands but, if the temperatures go back down, they will re-form the winter cluster. In short, honey bees are just like us—they try to keep warm and well fed during the long and cold winter days, then go out and frolic in the sun the very first chance they get.