“Astronomers use the equinox to mark the transition from summer to fall in the Northern Hemisphere, which happens around Sept. 22 or 23 every year. The autumnal equinox is roughly the halfway point between our longest and shortest days of the year. Like the spring equinox in March, it’s one of only two days of the year when day and night are about 12 hours long everywhere on Earth. ” Washington Post

Click here to learn more about the spring (and fall) equinox.