The Autumn Equinox is the moment when the Sun appears to cross the celestial equator as it makes it journey southwards. This event is a key marker for the distinction between the seasons. It is the day when the northern hemisphere slightly tilts away from the sun marking the day when there is approximately equal amounts of daylight and darkness. But what actually is the Autumn Equinox and when is it this year?
Temperatures are beginning to drop and days are drawing to a close earlier in the day, but the official marker of the arrival of Autumn has not yet arrived.
The September Equinox, also known as the Autumn Equinox, is the moment when the Sun as viewed from the Equator rises due east and sets due west.
Before the Autumn Equinox, the Sun rises and sets more northerly and afterwards, it rises and sets more southerly.
It marks the end of summer and the beginning of autumn for the northern hemisphere, while conversely it marks the end of the winter and the start of the spring in the southern hemisphere.
Autumn Equinox date: What is the Autumn Equinox? (Image: GETTY)
Each year, there are four seasons: Spring, Summer, Autumn and Winter.
Throughout the year, there are one or two days when the length of the night and day are roughly the same, this is known as the Autumn and Spring equinox.
This means in most places around the world there will be approximately 12 hours of daylight and darkness.
They take place in September and March but the dates change according to the progression of the Sun.
Each year, the Autumn Equinox usually takes place between September 21 and 24.
Autumn Equinox date: A scientific chart showing how