On the day of the September Equinox, day and night are almost the same length. This marks the end of summer in the Northern Hemisphere and the beginning of fall. Meanwhile, in the Southern Hemisphere, it's the first day of spring. On September 22 at 12:43 UTC, the Sun crosses the celestial equator, causing most places to have over 12 hours of daylight. https://www.timeanddate.com/calendar/facts-about-september-equinox.html