The arrivals of pumpkin spice lattes and chunky knits in store window displays might have felt premature a couple weeks ago, but this week makes it official: Fall is here. Though the recent spate of oddly warm days might suggest otherwise, this Friday, September 22, at 4:02 p.m. is the autumnal equinox.
Equinoxes occur twice a year — the first, the spring equinox, took place in March. According to EarthSky, the astronomical occurrence is owed to the tilting of the Earth's axis as it orbits the sun. The two equinoxes occur when the sun is directly above the equator. So on the day of the equinox, the day and night in both hemispheres will be about equal — "equinox" derived from the Latin words for equal and night — this will change in the weeks and months following.
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This Friday marks the shift of which hemisphere receives more direct sunlight for the next six months. So while those of us in the northern hemisphere are in for shorter days and cooler weather, those in the southern hemisphere are readying for the longer, hotter days of summer.
Historically, the September equinox was celebrated as a change of season and the arrival of the harvest for many cultures. The Mayan Pyramid of Kukulcan in Chich'en Itza, Mexico was designed so that sunlight would shine down its staircase during both the spring and autumn equinoxes.
For us, beach season is traded for cozy days by the fire, iced coffee abandoned for hot chocolate, and frilly sundresses packed away to make room for warmer layers and sweaters. Besides glorious orange and red foliage, and an Instagram feed packed with hiking photos, you can expect darker days, since the sun rises later and falls earlier.
Enjoy the September equinox, and if you still have a couple things on your summer bucket list, try to squeeze them in this weekend.