Coastlines washed by cold currents normally have scanty rainfall. This is because cold ocean currents originate from polar regions, where the air is cold and dry. As these currents move towards the equator, they cool the overlying air, which causes any moisture in the air to condense and form clouds. However, since the air is cold and has little moisture to begin with, the resulting rainfall is usually minimal. Therefore, coastlines that are washed by cold ocean currents generally experience low levels of rainfall.