What is the summer solstice?

Summer solstice is the tenth solar term among the 24 solar terms, and it is also the fourth solar term in summer. There is an agricultural proverb circulating among the people that "eating noodles from the summer solstice will shorten the day". Since the summer solstice, the days have been shortened, while the nights have become longer and longer.

For the summer solstice, the ancients explained it this way: "The days are long and the shadows are short, so it is called the summer solstice", which means that this day is the longest day in a year and the night is the shortest. Among them, "solstice" means extreme, not "arrival". In the northern part of the Arctic Circle, there will be an extreme day. Astronomers say that the summer solstice is the sun.

The summer solstice is the northernmost day of the sun in a year, the limit of the sun's northward movement and the longest day in the northern hemisphere. The higher the latitude, the longer the days. This is because the "long day and short night effect" caused by the tilt of the earth's rotation axis is more obvious as it approaches two levels. On the day of the summer solstice, except the south pole of the Antarctic circle and the polar night area, the sunrise direction in all parts of the earth starts from the northeast and sets in the northwest. The summer solstice is the northernmost day of the sun in a year and the limit of the sun's northward movement. On this day, the northern hemisphere gets the most solar radiation, almost twice as much as the southern hemisphere. After the summer solstice, the Tropic of Cancer and its northern region, the midday sun altitude angle also began to decrease.