What happens during the Autumnal Equinox on September 21st?

During the Autumnal Equinox, which occurs around September 21st, the primary characteristic is that daylight hours are equal to night hours. This phenomenon occurs because the Sun is positioned directly above the equator, leading to a balance in the amount of sunlight received in both the northern and southern hemispheres. On this day, locations at the equator experience approximately twelve hours of daylight and twelve hours of darkness.

This event marks a transitional point in the seasons, where days start to become shorter than nights in the northern hemisphere, signaling the onset of autumn. It contrasts with both the Vernal Equinox in March, when the opposite occurs, and the solstices, which mark the longest and shortest days of the year. Understanding the equinox helps in comprehending the relationship between the Earth's tilt and orbit around the Sun, as well as its effect on seasonal changes.