Winter is fragile, and needs taking care of.
Spring is like a punk kid, all temper and fun; it is changeable and in a hurry. Summer can take care of itself, it is ticking away like an old clock that knows its job. Autumn is the time of culmination, of busy-ness, and result.
But winter needs someone to show it the way, to shape it and to make it through. Winter is the child of the year, dependent — it is the time to shape and nurture. It is the time that makes all the rest of the year work or not. Foundations are laid. Character is revealed. It is the time of questing and trying on new things.