White dew is the watershed between heat and cold, and "white dew" represents the end of summer heat. After entering the White Dew Solar Term, the summer monsoon is gradually replaced by the winter wind, and the cold air is gradually frequent in the south. In addition, the position of the sun directly on the ground moves south, the sunshine time in the Northern Hemisphere is shorter, the sunshine intensity is weakened, the night is often sunny and less cloudy, and the ground radiation and heat dissipation is fast, so the temperature decline is gradually accelerated. There is a saying that "White Dew and Autumn divide the night, cool the night".
