Monday morning at 3:50 am EDT, the Sun will be directly over the equator, marking the official beginning of autumn.
Generally speaking, we consider this to be a day when all locations on Earth experience an equal amount of daylight and an equal amount of darkness.
With modern timekeeping, we know this isn’t true, but it’s a good story to keep around. You can be certain that the Sun will rise directly east and set directly west today.
From this day forward, darkness will dominate daylight until the Solstice happens on December 21nd, the first day of winter.