Cold dew is the seventeenth solar term among the twenty-four solar terms in the lunar calendar, and is the fifth solar term in autumn.Cold dew means that the temperature is lower than that of white dew, and the dew on the ground is colder and is about to condense into frost.The three solar terms of white dew, cold dew and frost all represent the phenomenon of water vapor condensation, while cold dew is the transition from cool to cold climate.