What is the longest day in a year?

Summer solstice is one of the 24 solar terms. Every year on June 2 1 or 22 of Gregorian calendar, the sun moves to 90 degrees of the yellow meridian, which is the summer solstice. At this time, the position of the sun directly on the ground reaches the northernmost point of the year, almost directly on the Tropic of Cancer, and the sunshine time in the northern hemisphere is the longest. After the summer solstice, Yin Qi began to grow and Yang Qi began to decline.

"However, the summer solstice is not hot." "The summer solstice is already three years old." Although the summer solstice indicates that the hot summer has arrived, it is not the hottest time. After the summer solstice, the temperature will continue to rise for some time, and about twenty or thirty days is the hottest weather.

Meteorological changes:

Although the summer solstice has the longest day and the highest sun angle, it is not the hottest time of the year. Because, close to the surface of the heat, at this time still continue to save, did not reach the maximum time.

As the saying goes, "it's hot in dog days." The "dog days" in 20 18 last from July 17 to August 26th. The real high temperature weather is around beginning of autumn from mid-July to mid-August, with the highest temperature in all parts of the country, and the highest temperature in some areas can reach about 40℃.

After the summer solstice, the ground is heated strongly and the air convection is strong. Sudden thunderstorms are often easy to form in the afternoon to evening. Because of the small rainfall range, people call it "summer rain dividing fields" Liu Yuxi, a poet in the Tang Dynasty, skillfully used this weather to write a famous poem, "The east rises and the west falls, and the road is sunny and sunny."

Baidu Encyclopedia-Summer Solstice