Aquarius is the middle of winter, fixed and air. Nothing is starting; the season is simply being borne.
Saturn ruled it traditionally, and Uranus took over after 1781. As with Scorpio, both schemes remain in use — the modern reading emphasises invention, the traditional one endurance, and the sign reads quite differently depending which you take.
It is an air sign despite the water-bearer symbol, which trips up almost everyone at some point.
Traditionally attributed
Detachment, principle, invention, and coolness where warmth is expected.
Listed because it is what the tradition says, not because this site can check it. Everything above this line is geometry; everything in it is convention.