When is the annual autumnal equinox?

1, and the autumnal equinox usually falls from September 22nd to 24th of the Gregorian calendar every year. The climate in the south began to decline from this solar term. First, on this day, the sun reaches the yellow meridian 180, that is, the autumn equinox. The sun shines almost directly on the equator of the earth, and the length of day and night is equal all over the world.

2. After the autumnal equinox, the direct point of the sun continues to move from the equator to the southern hemisphere, and the days in the northern hemisphere become shorter and the nights become longer, that is, the days in a day are shorter than the nights; In the southern hemisphere, the days are long and the nights are short, which means the days are longer than the nights. Therefore, the autumnal equinox is also called the landing point. At the North Pole and South Pole, on the day of the autumn equinox, the sun is on the horizon all day.