<P> In meteorology , precipitation is any product of the condensation of atmospheric water vapor that falls under gravity . The main forms of precipitation include drizzle , rain , sleet , snow , graupel and hail . Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor , so that the water condenses and `` precipitates '' . Thus , fog and mist are not precipitation but suspensions , because the water vapor does not condense sufficiently to precipitate . Two processes , possibly acting together , can lead to air becoming saturated : cooling the air or adding water vapor to the air . Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud . Short , intense periods of rain in scattered locations are called `` showers . '' </P>
what are the four main types of precipitation
drizzle rain sleet snow graupel hail