What is the longest and shortest day in a year?

In a year, the solstice in winter is the longest and the solstice in summer is the shortest.

In winter solstice, although the sun is low and the days are short, the temperature in winter solstice is not the lowest in meteorology. In fact, because there is still "accumulated heat" on the surface, it is usually not very cold before the winter solstice, and the real cold is after the winter solstice.

On the day of summer solstice, the height of the noon sun is the highest in all parts of the northern hemisphere north of the Tropic of Cancer, and the daytime reaches the longest in a year. After the summer solstice, the height of the sun decreases day by day. However, for places south of the Tropic of Cancer in the northern hemisphere, sunshine is still increasing after the summer solstice.

Extended data:

On the solstice after winter, the height at which the sun rises is not the yang spirit in the concept of "yin and yang". The yang in "winter brings forth the sun" belongs to the sun, not yin and yang. They are different concepts. So is the solstice in summer. The arrival of the summer solstice solar terms shows that the sun is the highest and the day is the longest in the northern hemisphere, which is not the highest day in the concept of yin and yang.

"Yin-Yang and Five Elements" belong to the category of "trunk and branch", and the growth and decline of "Yin-Yang" is based on "trunk and branch", not on the deviation of direct sunlight. According to the law of solar terms, beginning of spring is the starting point of the rising of "Yin and Yang" qi in Yang Qi. Since the beginning of spring, Yang Qi has changed and Yang Qi has risen. The solstice in winter is the starting point for the return of the sun. Since the winter solstice, the sun has returned to the north, and the days in the northern hemisphere have increased day by day.

The solstice in summer is the starting point of the sun's southward movement. After the summer solstice, the days in the area north of the Tropic of Cancer become shorter and the light becomes weaker. However, for the area south of the Tropic of Cancer, after the summer solstice, the sun shines directly again, and the days are not short, and the light is still increasing.