During an equinox, places around the globe experience nearly equal amounts of daytime and nighttime. The second occurrence this year happens on Sunday.

The autumnal equinox heralds the arrival of fall in the northern hemisphere, and it's just around the corner. Here's what to know.

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.

The first day of fall is on Sunday, Sept. 22, 2024, in the Northern Hemisphere. These are just two different ways to carve up the year. Meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles.

People participate in rituals during a fall equinox celebration on an embankment of the Neris River near King Mindaugas' Bridge in Vilnius, Lithuania, in 2019. Twice a year, the sun doesn’t play favorites.

Today marks the autumnal equinox, or the first day of astronomical fall. Have you ever wondered why it occurs on a different day and at a different time each year? Let’s break it down! Let’s start with the basics.