When is the longest day? When is the longest day of the year in China?

1. The summer solstice is the longest day and the shortest night in the northern hemisphere. On the day of the summer solstice, except for the polar regions of the Arctic and Antarctic circles, the sunrise direction in all parts of the earth starts from the northeast and sets in the northwest.

2. Every June 2 1 or so. The direct point of the sun is on the tropic of cancer, with the longest day and the shortest night in all parts of the northern hemisphere. The higher the latitude in the northern hemisphere, the longer the day and the shorter the night, and the arctic circle appears extremely daytime. The higher the latitude in the southern hemisphere, the longer the night and the shorter the day, and the polar night phenomenon appears in the Antarctic circle. The farther away from the tropic of cancer on the earth, the more inclined the sun's rays are, and the less solar heat is obtained. In contrast, the northern hemisphere gets more heat than the southern hemisphere at this time. Generally speaking, June, July and August are summer in the northern hemisphere and winter in the southern hemisphere.

3. Characteristics of summer solstice: Although 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, "Hot days are in dog days", and the real hot weather is calculated by summer solstice and beginning of autumn. From mid-July to mid-August, the temperature is the highest in all parts of China, and the highest temperature in some areas can reach about 40 degrees. On the day of summer solstice, the direct position of the sun on the ground reaches the northernmost point of the year, almost directly to the Tropic of Cancer, and the daytime in the northern hemisphere is the longest, and the farther north it is, the longer it is. After the summer solstice, the position of direct sunlight on the ground gradually moved southward, and the days in the northern hemisphere became shorter and shorter.