Question

Why are cloudy nights generally warmer than clear ones?

Short answer

The heat emitted by the earth is trapped by the clouds, and this leads to a warmer climate during cloudy nights compared to clear ones.

Step-by-step solution

Explain why cloudy nights make the earth warm

Clouds are formed by the warm air in the atmosphere. This cloud acts as a blanket for the atmosphere. The earth gets heated during the daytime by the radiation emitted from the sun. At night, the earth emits infrared radiation.

The warmer radiation heats the air and rises upwards in the atmosphere. The clouds are formed in the top layer of the atmosphere. As a result, it serves as a barrier between space and Earth. The heat emitted from the earth will get trapped by the clouds, which will then emit the heat back onto the earth, thus making the earth warmer.

Compare the warmer effect caused by a cloudy night with a clear one

If there are no clouds, the heat emitted by the earth won’t get trapped in between. So, they directly escape into space and the temperature on earth slows down, while in the case of a cloudy night, the heat can’t escape and return back to earth and cause a warmer climate.

So, cloudy nights are warmer than clear ones due to their capability to trap heat emitted from the earth.