South America Climate varies widely due to the sheer size of the continent, its geographical location, winds and ocean currents. South America's climate is dominated by relatively warm regions, yet the continent can generally be grouped into 4 zones, tropical, cold, dry and temperate.
Along the Equator, running from the Pacific Ocean eastward to the Atlantic Ocean is a wide climate zone of the continent that is tropical, humid and wet. As the land moves north and south of the equator the amount of rainfall diminishes. Rainfall in the wettest part of the region, Colombia into Brazil's northwestern section of the Amazon Basin, also South America's northeastern coastline, with the countries of Suriname, Guyana and French Guiana can see more than 350 inches a year. Yet tropical, the region will have periods of dry weather. Several major areas of South America will see rainfall well above 80 inches a year. A more Tropical wet and dry climate, the countries of Venezuela, the savannahs of Guyana and Suriname as well as the southeastern portion of Brazil fall into this climate zone.
South America climate has a zone of humid ocean air that lies on the southwestern portion of Chile. Humid winds blowing off the Pacific Ocean give the southern coastal portions of Chile large amounts of rain before hitting the Andes Mountains. On the other side of the Andes, Patagonia Argentina is robbed of this moisture and will only see around 10 inches of rainfall a year.
The Andes Mountains extending the whole length of South America from Venezuela into Chile gives South America climate a zone resulting in cold dry air, leaving the mountains snow covered year round.
The Atacama Desert, extending from southern Peru into northern Chile is the world’s driest desert. Continuing north along the Peru Coast, this South America climate zone is void of moisture due to the Peru Current flowing north and unable to hold moisture in the cool dry air. Argentina's Gran Chaco region has the hottest temperatures in South America.
El Nino, (the child) is a weather phenomenon that changes the South America climate as well as other portions of the world. Occurring every two to seven years, the Peru Current weakens and warmer water enters the region thus flowing southward along the Pacific Coast of South America, providing much needed rainfall to the dry region of western coast of South America.