What's the Autumn Equinox?

Winter is officially coming. We blew by the longest day of the year with June’s summer solstice, and are coming up on the autumnal equinox on Wednesday—the day when the sun passes directly over Earth’s equator. In the northern hemisphere, this marks an end to the long days of summer and the beginning of winter’s endless dark nights. For the other half of the planet, Wednesday is the vernal equinox, signaling the beginning of spring. Even though the equinox happens twice a year, every year, there are a lot of misconceptions about this seasonal transition.