The amount of precipitation, including rain, that falls on the contiguous United States each year varies greatly from one region to the next. Assessing an average for the entire nation is somewhat problematic, but it is possible to determine that if all the rain that falls during an average year were to occur during a single nationwide storm, the entire country would be covered to a depth of about 30 inches (76 cm). Many factors affect what happens to rain after it reaches the ground, including the topography of the land, the presence of or lack of vegetation and the degree of urbanization in the area.
More facts about US rain patterns:
- Louisiana is considered the wettest of all the contiguous US states, with an average annual rainfall of 56 inches (142 cm). Nevada is the driest state, with an average annual rainfall of less than 10 inches (25 cm).
- Yuma, Arizona, is considered the driest city in the US, with an average annual precipitation of less than 3 inches (7.6 cm). By contrast, the city of Quillayute, Washington, is the wettest in the contiguous US, with average annual precipitation of 105.50 inches (268 cm).
- Hilo, Hawaii, is the wettest city anywhere in the US, with an average annual rainfall of 128 inches (325 cm).