Precipitation is the process of falling of moisture from the base of cloud in different forms like rain, snow and hail. Various types of precipitation are- i) Convectional (convective rise of warm air), ii) Orograhic (Rise caused by mountain barrier), and iii) Frontal.

a) At ground: In winter season, long winter nights facilitate contact cooling. The cooling of the moist air column below its dew point temperature makes the ground object as hygroscopic nuclei facilitating condensation. This category includes dew and frost.

1.     Dew– It is typical to lower latitudinal and altitudinal locations. These are the deposited water droplets. (Dew point temperature: the temperature to which moist air is cooled at constant pressure and at constant water vapor to reach saturation with respect to water).

2.     Frost– These are the deposited minute ice-crystals. It occurs in higher latitudes and altitudinal areas where temperature is below the freezing point of water. (Frost point temperature: the temperature to which moist air is cooled at constant pressure and at constant water vapor to reach saturation with respect to ice).

b. Near ground condensation

1. Fog– Fog is simply a ground level cloud. It is defined to be the visible aggregate of suspended ice-crystals and water droplets. Various types of fog are radiation, advection, frontal fog etc.

c) Atmospheric condensation: The condensation form that develops throughout the year and throughout the world barring the exception of extreme Polar Regions is clouds. Clouds can be defined as the visible aggregate of the tiny ice crystals and minute water droplets.