Coasts and mountains can make an area more inclined to receive a lot of rainfall. For example in Hawaii, the Pacific High wind current draws a lot of moisture from the ocean and brings it onto the land. When the moisture hits a mountain, the air becomes condensed and clouds form, ultimately resulting in large amounts of precipitation. However, although the mountains make more rainfall possible, they also contain the rain to certain areas because the clouds cannot easily pass over the mountain.
Large bodies of water can increase the likelihood of rainfall because wind patterns that draw moisture from the water can increase cloud formation, which is aided by convection, the process by which hot and less-dense air rises. Generally, clouds are the thickest in the late afternoon when the sun's heat facilitates evaporation the most. This process can lead to more rainfall in areas located near large seas, lakes, rivers, oceans or ponds.
In general, as elevation increases on a mountain, the amount of rainfall increases. However, the arrangement of mountain peaks, troughs, valleys and cliffs can influence rainfall. The windward side of a mountain, or the side the wind hits, typically has more rainfall than the leeward side. Studies have found that basins within mountain ranges receive particularly high rainfall, potentially as a result of the mountains that surround them trapping moisture and helping form clouds.
Plateaus may receive a lot of rainfall, depending on their elevation and temperature. Low temperature, which is usually found in plateaus with lower elevation, tends to decrease the amount of rainfall. High temperatures have the opposite effect. Because plateaus usually have adjacent beds of rock, the runoff from the plateau's rainfall can increase the precipitation on the beds of rocks surrounding it. Plateaus protected by mountain ranges may have reduced rainfall.
