State the principal factors affecting the distribution of rainfall. Which are the wettest regions of the world?

The principal factors affecting the distribution of rainfall are:

1. Latitude — The latitudinal belt of maximum precipitation is found in the equatorial Zone between 8° N to 8° S along with the seasonal shifting of the Doldrums. The shifting of the Trade Winds causes winter rains in Mediterranean Regions in Europe. Trade Winds blow from North-East to South-West, they shed maximum moisture on the Eastern margins of the continents and western margins are left dry.
2. Continents and oceans — Places which are located away from the sea in the interior receive relatively less precipitation than coastal areas.
3. Mountain Barriers — They play a great role in the world distribution of precipitation by causing orographic rainfall on the windward side while the leeward side remains dry or receives little rainfall.

The latitudinal belt between 8° N to 8° S is the wettest region of the world.