When is the Autumnal Equinox?
In the Northern Hemisphere, the autumn equinox takes place around September 22 and in the Southern Hemisphere, it does so around March 20. Due to the erratic nature of the Earth’s orbit around the sun, these dates may fluctuate from year to year. The precise date of the equinox is determined by the precise moment when the sun appears to move from north to south over the celestial equator. This can happen a day or two earlier or later than September 22nd, when it typically does. The autumnal equinox signifies the change from summer to fall in the Northern Hemisphere and the change from spring to summer in the Southern Hemisphere. On the equinox day, the length of day and night is roughly equal throughout the planet. In the Northern Hemisphere, the days grow shorter and the nights grow longer after the equinox, whereas the opposite happens in the Southern Hemisphere.
Year | Autumnal Equinox (Northern Hemisphere) | Autumnal Equinox (Southern Hemisphere) |
2022 | Thursday, September 22 | Sunday, March 20 |
2023 | Saturday, September 23 | Monday, March 20 |
2024 | Sunday, September 22 | Tuesday, March 19 |
2025 | Monday, September 22 | Thursday, March 20 |
Autumnal Equinox: Definition, Dates & Facts
Autumnal Equinox is often referred to as the September equinox or the fall equinox. The Autumnal Equinox is an astronomical event that takes place twice a year, on March 20 in the Southern Hemisphere and around September 22 in the Northern Hemisphere. Autumn equinox designates the time when the sun appears to move from north to south across the celestial equator, a fictitious line in the sky above the Earth’s equator.