The summer solstice is the 1th of the 24 solar terms. Fight refers to noon; The yellow meridian of the sun is 9; It is celebrated on June 21~22 of the Gregorian calendar. On the day of the summer solstice, the position where the sun shines directly on the ground reaches the northernmost point of the year, almost directly on the Tropic of Cancer. At this time, the daylight time in all parts of the northern hemisphere reaches the longest in the whole year. For the Tropic of Cancer and its northern area, the summer solstice is also the highest day of the year at noon.

the summer solstice is a turning point for the sun to travel northward. After the summer solstice, the direct point of the sun began to move south from the Tropic of Cancer, and the days in the northern hemisphere began to shorten gradually. For the area north of the Tropic of Cancer in China, after the summer solstice, the height of the noon sun began to decrease day by day; For the area south of the Tropic of Cancer in China, the height of the noon sun returns to the south after the summer solstice, and it begins to decrease day by day after the sun shines again.

high temperature, high humidity and occasional thunderstorms are the weather characteristics after the summer solstice. The summer solstice is in the middle of summer, that is, noon, which belongs to the sun; Although the summer solstice is full of yang and the longest day, it is not necessarily the hottest day of the year, so the heat near the surface is still being accumulated and has not reached the maximum.

The summer solstice is not only one of the 24 solar terms, but also a festival in the "Four Seasons and Eight Festivals" in ancient times. Since ancient times, people have the custom of worshipping gods and ancestors on the summer solstice. In addition, after the summer solstice, people generally eat Qingbuliang soup, herbal tea and sour plum soup to escape the heat.