How does cloud cover affect surface temperatures during the night?

Cloud cover has a significant influence on surface temperatures during the night because clouds act as a barrier to the heat escaping from the Earth's surface into space. When skies are clear, heat can radiate away from the ground, leading to a rapid drop in surface temperatures. However, when clouds are present, they trap some of this outgoing radiation, resulting in a warming effect.

During the night, particularly in situations with substantial cloud cover, the clouds absorb and re-radiate longwave radiation emitted from the Earth. This process helps to keep the surface temperatures higher than they would be under clear sky conditions. Consequently, nights with extensive cloud cover tend to be milder compared to those with minimal or no cloud cover.

In essence, the correct choice reflects the role of clouds in retaining heat and influencing nocturnal temperatures, illustrating how they can maintain warmer conditions overnight.