The autumnal equinox means the official entry into the fall season. Autumn Equinox, "points" that is, "equal parts", "half" meaning, the day of the autumnal equinox sunlight almost directly on the Earth's equator, the day and night around the globe is long. Autumn equinox after the location of direct sunlight moved to the southern hemisphere, the northern hemisphere to get less and less solar radiation, the ground heat loss is more, the speed of temperature reduction significantly accelerated. By the time of the autumnal equinox, the summer heat has been eliminated, the weather turned cool, summer and cool phase separation.

Extended information

"Autumn Equinox" means two things:

1, equal day and night time, the sun reaches 180 degrees of yellow longitude on this day, direct sunlight on the Earth's equator, so most of the world on this day of the 24 hours of day and night are divided into equal parts, each 12 hours. After the autumnal equinox, the sun's point of direct sunlight began to enter the southern hemisphere by the equator, the northern hemisphere began to short days and long nights, the day began to be shorter than the night within a day; near the North Pole is also about to usher in a year of six consecutive months of long night and six consecutive months of inextinguishable . Starry sky.

2, the climate from hot to cool. According to China's ancient to spring, summer, autumn, winter for the beginning of the four seasons of the seasonal division of law, the autumnal equinox in the 90 days of autumn, the equal division of the autumn. Autumn equinox in the annual calendar September 22, 23 or 24, for the traditional Chinese festival of the twenty-four seasons, when the sun reaches 180 degrees of yellow longitude.

Weather characteristics of the Autumn Equinox:

At the time of the Autumn Equinox, most of China has already entered the cool autumn, and the cold air moving southward meets with the gradually decaying warm and humid air, producing precipitation again and again, and the temperature drops again and again. As people often say, it has reached the time of "an autumn rain a cold", but the daily precipitation after the autumnal equinox will not be very large. At this time, the south and north of the field cultivation is different.