Influence of Cloud and Rainfall on Air Temperature
The sun heats the Earth and it causes water on its surface to evaporate and form water vapour. As hot air contains fewer molecules per cubic meter and cold air contains more, the warm air rises up over colder air, expands and becomes cooler and the water vapour starts condensing into tiny droplets of water. As the air rises further, its temperature drops further and the air contracts. Then the air cannot hold the moisture and releases some of it.
The moisture thus released, clings to dust particles and condenses into tiny droplets of water. These droplets float in the air and appear to us as ‘Fog’ or ‘Cloud’. As the air cools further, these droplets of water join and form larger drops and fall to the ground as, ‘Rain’.
Clouds have both cooling and warming effects on Earth's surface. The high, wispy clouds actually keep Earth warm, like a blanket, by preventing heat from escaping into space. However, the white-colored cloud tops promote cooling of Earth's surface by reflecting short-wave radiation from the sun
Due to rainfall, the temperature of the atmosphere near the surface decreases, while water vapour in the atmosphere near the surface increases. If sky is clear, heat emitted from the earth's surface due to rainfall freely escapes into space, resulting in decrease of temperatures. However, if clouds are present even after the rainfall, some of the heat emitted from the earth's surface due to rain, is trapped by the clouds and re-emitted back towards the earth.