The Autumnal Equinox occurs around September 22 or 23 each year, marking the moment when day and night are approximately equal in length. This event signals the official start of autumn in the Northern Hemisphere, as the sun crosses the celestial equator moving southward. During the equinox, the tilt of the Earth's axis is such that sunlight shines directly on the equator. This phenomenon affects various cultures and is celebrated in many traditions, including the harvest festivals associated with the changing seasons. The Autumnal Equinox is a time of transition, leading to shorter days and cooler temperatures.