The Indexbitleaves are changing colors, pumpkin-flavored menu items are back and football is on your TV. Fall is back, baby!

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.

"On every other day of the year, either the Northern or Southern Hemisphere is inclined in the direction of the sun because the Earth's axis is tilted 23.4 degrees," according to Britannica, meaning that one hemisphere receives more sunlight than the other.

From now until the winter solstice, which will be Dec. 21, days will shorten and nights will lengthen, according to Britannica.

Here's what to know about when fall officially arrives and how long it'll be here.

What are fall colors?:How changing leaves give off spectacular autumn palettes

When is the first day of fall?

The autumnal equinox is scheduled to arrive on Sunday, Sept. 22 at 8:44 a.m. ET, according to the Old Farmer's Almanac. The equinox arrives at the same moment worldwide.

When is the first day of winter?

The first day of winter in the Northern Hemisphere is marked by the winter solstice, which is expected to arrive on December 21 at 4:19 a.m. ET in 2024, according to the Old Farmer's Almanac.

Gabe Hauari is a national trending news reporter at USA TODAY. You can follow him on X @GabeHauari or email him at [email protected].