1, spring equinox, one of the twenty-four solar terms, is the fourth solar term in spring. Doo refers to non, the sun's yellow longitude reaches 0 °, in the annual calendar March 20-22 cross section.

2, the equinox, the Sun's point of direct sunlight on the equator, after the Sun's point of direct sunlight continues to move north, so the equinox is also known as the "ascending fraction". In ancient times, it was also known as the "sun", "day and night", "the month of spring".

3, the vernal equinox is a relatively important season, it is important in astronomy: the northern and southern hemispheres day and night. In terms of climate, there are also more obvious characteristics. Since this day, the position of direct sunlight continues to move from the equator to the northern hemisphere, the northern hemisphere around the day is longer and night is shorter, the southern hemisphere around the night is longer and shorter day.

4, the vernal equinox, in addition to the Tibetan Plateau, Northeast, Northwest and North China outside the northern regions have entered the bright spring. At this time of year, the climate is mild, abundant rainfall, sunny, most of China's overwintering crops into the spring growth stage.