The autumnal equinox, also known as the September equinox, occurs the moment the sun crosses the celestial equator.<br />During the day this occurs, the length of night and day are nearly equal, as the sun is shining directly perpendicular to the equator.<br />It is for that reason we call it an “equinox,” which is derived from the Latin word for “equal night.”<br />The September equinox occurs on either the 22, 23 or 24 of the month.<br />For the Northern Hemisphere, this signals the first day of fall, while in the Southern Hemisphere, it signals the first day of spring.<br />Earth’s axis is typically tilted at a 23.4 degree angle, which means either the southern or northern hemisphere is more tilted towards the sun.<br />During that time period and until the equinox, that hemisphere receives more sun than the other,<br />causing the varying seasons of winter and summer.
