We name them for the full moons which in turn are named for the cycle of life throughout the year. Wolf, Storm, Carp, Seed, Goose, Rose, Mead, Wort, Barley, Blood, Snow, Hearth. I suppose we'd be moving from Hearth into Wolf at the moment, though it's cold enough that most people would probably rather stay close to their hearths anyway.
It's very different. I don't much like being underground either, though at least there's plenty of room to move around and it's not so dark.