The official first day of fall, otherwise known as the autumnal equinox, is this weekend in the Northern Hemisphere. According to Encyclopedia Britannica, it is one of only two days, the other being the vernal equinox, when the sun is directly above the Equator, essentially dividing night and day into equal portions.

Sept. 22, marks the first day of the autumnal equinox in the Northern Hemisphere, according to the Farmer’s Almanac. It begins approximately at 8:43 a.m. ET. Meanwhile, meteorological fall begins on Sept. 1 and makes it easier to keep seasonal weather records, according to FOX Weather.

BREVARD COUNTY, FLORIDA – Welcome fall! The autumnal equinox—the September equinox or the fall equinox—arrives on Sunday, September 22. Not only do temperatures drop, but plant life slows down, and so do we. Read about the first day of fall, plus some fun facts and folklore.

The equinox has no relationship to Houston’s weather, and the city’s climate afterwards isn’t guaranteed to bring cooler or warmer temperatures.

Twice a year, the sun doesn’t play favorites. Everyone on Earth is seemingly on equal status – at least when it comes to the amount of light and dark that they get.

If you get up early enough, you can experience an equinox sunrise. The autumnal equinox heralds the arrival of fall in the northern hemisphere.