In the Northern Hemisphere the Autumn equinox typically is September 22 or 23, as the Sun crosses the celestial equator going south. This year the Autumn Equinox is September 22. The word “equinox” comes from Latin aequus, meaning “equal,” and nox, “night.” On the equinox, day and night are roughly equal in length. The Sun begins to rise later and nightfall comes sooner. Meteorological Fall/Autumn started September 1st. South of The Equator Spring starts when it is Autumn in the Northern Hemisphere.