The longest and shortest day of the year.

The summer solstice (June 22nd) is the longest and the winter solstice (65438+February 22nd) is the shortest. From summer solstice, the sun shines directly to the northernmost part of the year and the Tropic of Cancer. The daytime in the northern hemisphere is the longest, and the farther north it is, the longer it is. The winter solstice is the year with the shortest day and the longest night in the northern hemisphere. After the solstice in winter, the days will get longer.

Summer solstice and winter solstice are two very important solar terms in China lunar calendar. Winter solstice and summer solstice are relative to the direct sunlight point on the Tropic of Cancer. In fact, for our northern hemisphere, the summer solstice is closer to the apogee of the earth. Although the earth is farthest from the sun, the direct point of the sun is on the tropic of cancer in the northern hemisphere, so it is the beginning of hot summer, so it is called summer solstice. On the winter solstice, although the earth is closest to the sun, the direct point of the sun is on the tropic of Capricorn in the southern hemisphere, so it is the beginning of winter, so it is called the winter solstice.

The solstice in summer and the solstice in winter are two landmark points in the 24 solar terms. The summer solstice is generally on June 2 1 or 22, and the winter solstice is 65438+February 2 1 or 22, with a difference of half a year. The summer solstice is the longest sunshine time in the northern hemisphere, while the winter solstice is the opposite, which is the shortest sunshine time.

In the northern hemisphere, generally speaking, after the summer solstice, the weather will accelerate. Generally, it begins to enter the dog days after 10, that is, the coldest time of the year after the winter solstice, and counting nine begins after the winter solstice. As the saying goes, it is hot in dog days and cold in three or nine days, which is directly related to the solstice in summer and the solstice in winter.