The Old Farmer's Almanac on Instagram: "The autumnal equinox (AKA the September equinox or the fall equinox) arrives on Monday, September 22 🍂 Based on the astronomical definition of seasons, the autumnal equinox marks the first day of fall. But according to the meteorological definition of seasons, the first day of fall is usually considered to be September 1. Find out why! 🍂 Link in bio.⁠ ⁠ #oldfarmersalmanac #farmersalmanac #almanac #ofa #fall #autumn #weather #fallweather #fallvibes #sweat