Rainfall is a type of precipitation. the term “rainfall” can be used to define precipitation in the form of water drops with sizes larger than 0.5 mm. The other forms of rainfall are given as drizzle, snow, sleet, glaze and hail.Snow will form ice crystals which are usually combined to produce flakes. When the new snow holds an initial density ranging from 0.06 to 0.15 g/cc, it is usual to assume an average density of 0.1 g/cc.Drizzle is defined as the fine sprinkle of a number of water droplets with a size less than 0.5 mm and intensity at less than 1 mm/h is called drizzle. In this, the drops are very small, where they appear to float in the air.Moreover, Rainfall Has Mainly 3 Types :Relief rainfall - when warm and moist air rises up over mountains, it causes relief rainfall.Convectional rainfall - this rainfall usually happens during the summers, when the sun heats the land. Frontal rainfall - when a warm front meets a cold front then frontal rainfall takes place. in this, the warm air rises up and cools. this cooled down air condenses to form clouds and then rains heavily.