Introduction to the characteristics of vernal equinox solar terms Detailed explanation of the characteristics of vernal equinox solar terms

1, the vernal equinox, also known as "Japan-China", "Day-Night Equinox" and "Midspring Moon" in ancient times, coincides with March 20th or 2 1 of Gregorian calendar every year, and starts when the sun reaches 0 degrees (vernal equinox) of the yellow meridian. Because the length of day and night is average, spring is exactly half of 90 days, so it is called "vernal equinox". "Shi Ming Li Yi" said: "The dividing line is the point where Huang Chi meets. When the sun comes here, it is divided equally between day and night. "

2. The vernal equinox has two meanings: one is to divide the day and night equally, each of which is 12 hour; Second, it refers to the spring from beginning of spring to long summer in ancient times. The vernal equinox falls within three months of spring, and the spring is divided equally. The vernal equinox is also a season in which yin and yang are balanced, day and night are equal, and cold and summer are equally divided. The so-called "spring equinox, Yang Yang is also half-phase, so it is cold and hot day and night."

3. In ancient China, the vernal equinox was divided into three periods: "First-class birds arrived; Second, wait for Lei Nai to make a sound; Third, wait for electricity. " It means that after the vernal equinox, swallows will fly from the south, and the sky will thunder and lightning when it rains. On the vernal equinox, the sun shines directly at the equator, and day and night are almost equal. Then the direct sunlight position gradually moved northward, and the days were long and the nights were short. With the arrival of the vernal equinox, the rainfall increased obviously, and the national average ground temperature reached 10℃, showing a scene of grass growing and warblers flying.