The amount of precipitation that a particular location receives is determined by a number of factors. These include the average temperature for an area, the maximum vapor limit, the humidity, the location of prominent land formations such as mountains, the proximity to oceans, the amount of wind, etc. The amount of precipitation that an area receives is referred to as that area’s average annual precipitation.

A location with a relatively low average annual precipitation would be rather desolate. Little water means that there will be less life. These areas are often called deserts.

Areas with high average annual precipitation are lush and bustling with life. These areas are often referred to as rain forests. Most of the Earth’s surface receives an average annual precipitation that lies somewhere between these two extremes.