In meteorology, precipitation is what happens when water from the atmosphere falls from the clouds, to the surface of the earth. This can be in the form of a liquid or solid state - from rain, snow, and sleet to hail. The small drops of condensed water that form clouds are too small to fall to the earth but when certain conditions prevail, they fall as precipitation. You might be interested to know that one-inch of rain falling over an area of one acre of land results in a colossal 27,154 gallons of water! (Our thanks to the US Geological Survey for that piece of information).