The evening of Wednesday, September 22, at 22:21 Greek time, typically begins in the fall, as the autumnal equinox will occur in the northern hemisphere, where Greece is located. At the same time, spring will begin in the southern hemisphere.
At the equator, night and day have almost the same duration. Then in the northern hemisphere the day will get shorter and the night will get bigger, until the latter will reach its zenith in the winter solstice of December.
In fact, in Athens the "equality" of day and night will occur a few days later, as on the very day of the autumnal equinox the equal day-night occurs only in places located directly on the earth's equator. In other areas above or below the equator, this happens a few days before or after the equator. Thus, in Athens, which is located about 38 degrees north of Ecuador, equality between day and night occurs after about four days.
Both equinoxes and solstices occur twice a year and mark the beginning of the seasons. From ancient times, across the length and breadth of the Earth, such phenomena were celebrated by the peoples, who gave them mythical meanings.