The Maipo Valley is Chile's most famous wine region. On one side of the region is the Andes Mountains, and to the other is the Coast line while Maipo Valley rests comfortably in the north center of the two. Average rainfall averages 300 millimeters a year making the region particularly dry. Any rain that does fall is do to spontaneous storms. The dryness of the region is the reason that irrigation is common in the Maipo Valley. Red grapes are dominate over white grapes in the region, with the main red being Cabernet Sauvignon. The leading white grape planted is Chardonnay.