There are various factors affecting the rainfall. They are as follows:

Latitude: Rainfall is influenced by the latitude. If the latitude is low, temperature will be high. Water vapour in the air depends upon the temperature. Rainfall depends upon the amount of water vapour in the air. Evaporating is highest in the equator and least at the poles. Therefore rainfall is more in the equator and less or nil at the poles.

Distance from the sea: Winds blowing from the sea bring rainfall over the coastal lands. But as these winds go further, they become drier. Therefore they do not bring much rainfall in the continents.

Mountains: There is heavy rainfall in the windward side of the mountains because the mountains obstruct the winds carrying moisture. But there is little rainfall on the leeward side of the mountains. This is because, by the time the winds cross the mountains, they lose much of their moisture and become dry.

Type and direction of winds: Winds blowing from the sea contain moisture, and therefore bring rain to the land over which they blow. But winds blowing from the land is dry, and therefore, they do not cause rains. Similarly winds blowing from the cold regions to hot regions cause little rainfall, while the winds blowing from hot regions to cold regions cause more rainfall.

Vegetation: Rainfall is more in a region where there is thick vegetation, i.e., forests, because the forests make the air cool. That is why, Assam and mainland areas get more rainfall than the desert and the malnad areas.