Why are solar terms closely related to climate change?

It turns out that the degree of climate change in a certain area first depends on the way the sun shines. When the sun shines vertically or nearly vertically, the ground receives more light and heat, and the climate will be hot; When the sun shines obliquely, there will be less light and heat, and the climate will be cold. Summer is coming, the position of the sun is getting higher and higher, the heat received by the ground is gradually increasing, and the heat released is also gradually increasing. When it reaches the summer solstice, it receives the most heat, but it takes about 1 month to reach the maximum, so the hottest weather does not appear in the summer solstice, but after the summer solstice about 1 month. It is no wonder that the summer solstice in the 24 solar terms is followed by a slight summer heat and a great summer heat. Summer is also hot. Similarly, the coldest time is not the winter solstice, but the winter solstice after about 1 month, so it is a great cold.

Working people in ancient China have long known that climate change is related to the position of the sun. Taking advantage of this dependence, the ancients invented watches to determine the seasons by observing the changes of the sun's shadow. The Book of the Later Han Dynasty recorded the eight-foot shadow length of each of the 24 solar terms, which was a record of the ancients setting seasons according to the length of the shadow.