September equinox
THE EQUINOX ON THE EARTH WHEN THE SUN APPEARS TO LEAVE THE NOTHERN HEMISPHERE AND CROSS THE CELESTIAL EQUATOR
Southward equinox; September Equinox; Spring equinox (Southern Hemisphere); Vernal equinox (Southern Hemisphere); Autumn equinox (Northern Hemisphere); Fall equinox (Northern Hemisphere); Vernal equinox (southern hemisphere); Spring equinox (southern hemisphere); Autumn equinox (northern hemisphere); Fall equinox (northern hemisphere); First day of autumn
The September equinox (or southward equinox) is the moment when the Sun appears to cross the celestial equator, heading southward. Because of differences between the calendar year and the tropical year, the September equinox may occur anytime from September 21 to 24.