Basic General Knowledge
On a night when the sky is clear, the temperature may dip considerably; on a cloudy night the temperature will usually dip much less. The reason for this difference is that
on a cloudy night the clouds are warm and therefore retard the cooling
current of air carry the heat away from the earth on a clear night
the clear sky allows the cold of outer space to reach the earth
the clear sky allows radiant energy to escape readily from the earth