The meaning of Chushu is to stop and stay.

End Heat

End Heat is a solar term that reflects changes in temperature. The original meaning of "place" is "to stop" and "to stay". "Shuowen Jiezi" says: Chu means stopping. "End of Heat" means that the hot and unbearable weather has come to an end and the heat has begun to subside.

Three summers and "three volts" both represent high-temperature and scorching weather. The curves on the time axis and the temperature axis are basically the same: when the summer comes, the dog days arrive; when the dog days disappear, the summer will end.

The twenty-four solar terms include "three summers", namely the minor summer solar term, the major summer solar term, and the final summer solar term. In order, they are the early summer heat, the heat stroke, and the late summer heat. There is also a solar term "Beginning of Autumn" sandwiched between the "Three Heats". After the Beginning of Autumn comes the end of the summer heat, which lasts longer. Longer summer heat is beneficial to crop growth and yield. The ancients called the period from the beginning of autumn to the autumnal equinox "long summer".

The Dog Days of Summer involve the four solar terms of Little Heat, Great Heat, Beginning of Autumn, and End of Summer. By the time of End of Heat, the Dog Days have passed or are coming to an end. The subsidence of summer heat is a slow process, and it does not mean that the weather will cool down immediately after the heat drops. Although it is still hot during the summer season, the temperature has begun to show an overall downward trend.

Knowledge expansion:

Sushu means "out of summer", and the high temperature will gradually fade away. After the summer heat, the direct sun point continues to move southward, solar radiation weakens, and the subtropical high pressure retreats southward. As the height of the sun continues to decrease, the heat it brings also weakens.

The end of the summer season means that the hot and unbearable weather is coming to an end. Although the weather is still hot during this period, it is already on a downward trend. The subsidence of summer heat is a slow process. It does not mean that the weather becomes cooler immediately after the summer heat drops. It usually takes until after the white dew for the real coolness to begin.

After the summer heat, the temperature gradually drops and the temperature difference between day and night gradually increases, but the daytime temperature is still high. The reasons for this phenomenon are: first, the direct point of the sun continues to move southward, and solar radiation weakens; second, the subtropical high pressure retreats southward in a leapfrog manner, and the Mongolian cold high pressure begins to show its strength.

Although the subtropical high pressure has made great strides to retreat southward after the end of summer, it will never give up its dominance and easily retreat to the sea in the Western Pacific. In the southern areas controlled by it, high temperatures are often experienced again at the end of the summer heat. This is the short-term hot weather "autumn tiger".

The length of autumn tiger season varies every year, generally lasting from half a month to two months. The reason for the formation of autumn tiger is that the western Pacific subtropical high pressure that controls China gradually moves southward in autumn, but then moves northward. Under the control of the subtropical high pressure, it becomes clear and cloudy, with strong sunshine and rising temperatures.