What does the vernal equinox mean?

Vernal equinox and solar terms mean equal seasons and equal days and nights.

The vernal equinox is one of the 24 solar terms and the fourth solar term in spring. The longitude of the sun reaches 0, and the festival is held on March 19-22 of the Gregorian calendar every year.

"Equinox" has two meanings. One is "season sharing". Traditionally, spring is between beginning of spring and Changchun, and the vernal equinox is in the middle of the two solar terms, which just divides spring equally. Another meaning is "equal day and night". At the vernal equinox, the sun shines directly on the equator, and the length of day and night is equal, each being 12 hour. The climate of the vernal equinox is characterized by warm and sunny weather.

The vernal equinox is of great significance in astronomy. On the day of the vernal equinox, the sun shines directly on the equator, and the northern and southern hemispheres are divided equally day and night. Since then, the direct position of the sun has continued to move from the equator to the northern hemisphere. In the northern hemisphere, the day begins to be longer than the night, while in the southern hemisphere, it is the opposite.

Meteorological changes of vernal equinox;

During the spring equinox, China has entered a bright spring except the Qinghai-Tibet Plateau, Northeast China, Northwest China and North China. The average daily temperature in all parts of China has steadily increased to above 0℃ except the mountainous areas in winter and the areas north of 45 north latitude.

At this time, the cold has passed and the temperature has risen rapidly, especially in North China and Huanghuai Plain. The daily average temperature rises to above 10℃ almost at the same time as the rainy areas along the Yangtze River and the south of the Yangtze River, entering a bright spring.

During the spring equinox and solar terms, the East Asian trough is obviously weakened, and the trough ridge activity in the westerly belt is obviously enhanced. From Mongolia to the northeast, there are often low-pressure activities and cyclone development. Low-pressure movement causes cold air to go south, and it is windy and windy in the north.