In 2024, the Autumnal Equinox arrives on Sunday, September 22. This date marks the start of Fall in the Northern Hemisphere and Spring in the Southern Hemisphere.

The September Equinox is the moment the Sun crosses the celestial equator, an imaginary line in the sky above Earth’s equator from north to south. This happens on September 21, 22, 23 and 24 in most years.

Whys is it called “Equinox?”
On the days of the equinoxes, the Earth’s axis is perpendicular to the Sun’s rays, meaning that all regions on Earth receive about the same number of hours of sunlight. In other words, night and day are, in principle, the same length all over the world. This is the reason it’s called an “Equinox,” derived from Latin, meaning “equal night.”

On September 22, New York City residents will enjoy a 12 hours and 8 minutes long day. Those in Amsterdam will get 1 more minutes of daylight with a 12 hours and 9 minutes long day. Even in Longyearbyen, one of the world’s northenmost cities, the day will last for 12 hours and 25 minutes. Moving southwards, Melbourne in Australia will see a 12 hours and 10 minutes long day. Johannesburg inhabitants will also enjoy a similar number of daylight hours. On the South Pole, the Sun will be up 24 hours. Perfect opportunity to see the Midnight Sun.

The Equinoxes and Solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. You can think of an Equinox as happening on the imaginary dome of our sky, or as an event that happens in Earth’s orbit around the Sun.