The difference in average precipitation is a product of many factors. Firstly, the latitude of the location is a very big determinant factors, how close or far a place is from the equator affects the climate that will be prevalent in the location. Other factors that can contribute to the difference include: the general climate of the location, altitude, distance away from the sea, ocean current, duration and intensity of the sunlight, land features in area, such as mountains, etc. All these factors will work together to determine the climate of a location.