Why is it cold when the cold dew and the first frost are typed?

Among the 24 solar terms, cold dew is the fifth solar term in autumn, and first frost is the last solar term in autumn. Since the cold dew began, the weather has gradually turned cold. So cold dew can mean cold; The first frost, on the surface, the first frost comes down, which means falling. Together, it may mean being left out.

Please accept the explanation, thank you!