To the white dew, the summer monsoon gradually replaced by the winter wind, the cold air turned to attack, coupled with the southern shift of the direct sun point, the northern hemisphere sunshine time is shorter, the light intensity is weakened, the ground radiation heat dissipation is fast, so the temperature drop speed is gradually accelerated. White dew basically ended the hot summer days, the weather gradually turned cool, cold dew condensation. The ancients used four times with five elements, autumn is gold, golden white, to describe the autumn dew, so the name "white dew".

After entering the white Dew solar term, the summer monsoon is gradually replaced by the winter wind, the cold air to the south gradually frequent, coupled with the position of the sun directly on the ground to the south, the northern hemisphere sunshine time becomes shorter, the sunshine intensity is weakened, the night is often sunny and less cloudy, the ground radiation heat dissipation is fast, so the temperature drop is gradually accelerated, there is "white dew autumnal equinox night, cool night" said.

After the white dew, the temperature difference between day and night gradually widened, although the temperature was higher at noon during the day, but the morning and night had a cool feeling. According to the modern scholar Zhang Baokun proposed "penultimate average temperature" to divide the four seasons standard, penultimate average temperature in 10-22℃ period for spring or autumn, according to this standard, from the beginning of the white dew solar term, all places began to enter autumn. At this time, the temperature difference between day and night across China can reach 8℃ -16 ℃, so white dew is a solar term with a large temperature difference in the year