Why is the earliest sunrise and latest sunset not on the winter solstice, and the earliest sunrise and latest sunset not on the summer solstice?

The time of sunset will change with the season and the latitude of each place. Traditionally, in the Northern Hemisphere, the earliest sunset occurs at the winter solstice and the latest sunset at the summer solstice.

But in fact, due to the influence of the yellow-red angle and the Earth's elliptical orbit, the earliest sunset will not fall on the winter solstice, but in early December; the latest sunset will not fall on the summer solstice, either. But at the end of June.

Even in equatorial areas, the times of sunrise and sunset will change slightly throughout the year, and these changes can be expressed by the path of the sun. The times of sunrise and sunset can track the path of the sun. calculated. In addition, sunlight is refracted by the Earth's atmosphere, so the sun can still be seen after it drops below the horizon, an illusion created every day at sunset.

Extended information

The winter solstice is about to enter the cold season, and people start counting nines to calculate the cold weather. Counting nine is a Chinese folk method of calculating the dates of cold and warmth. Folk proverb goes: "On the summer solstice, three Gengs fall, and on the winter solstice, Ren counts nine."

The counting of nine starts from the Ren day of the winter solstice, and one "nine" is counted every nine days, and so on. Generally, the "March and April" periods are the coldest and are the coldest periods of the year. When nine "nine days" (nine-nine and eighty-one days) are counted, spring is deep, the sun is warm, everything is full of vitality, and it is time for spring plowing.

The counting method has been passed down orally among the people in my country. It has a history but no records. As for when it originated, there is no exact information. The number nine is a summary of the experience of ancient people based on their production and life practices for generations, using some ecological reflections and weather signs in nature.

In the course of historical development, people in various places have also compiled various proverbs, songs and jingles based on the different climate conditions, landscape characteristics, agricultural weather and customs. "Nine-Nine Songs" can be found in all parts of the north and south, but the lyrics are slightly different.