the Central range are divided into two groups separated by the Sun Moon Lake Basin in the centre of the island. The Dadu and Zhuoshui Rivers flow from the western slopes of the Central Range through the basin to the west coast of the island. The Xueshan Range lies to the northwest of the Central Mountain Range, beginning at Sandiaojiao, the northeast tip of the island, and gaining elevation as it extends southwest towards Nantou County. Xueshan, the main peak, is high. The Yushan Range runs along the southwestern flank of the Central Range. It includes the island's tallest peak, the Yu Shan ('Jade Mountain') which makes Taiwan the world's fourth-highest island, and is the highest point in the western Pacific region outside of the Kamchatka Peninsula, New Guinea Highlands and Mount Kinabalu. The Alishan Range lies west of the Yushan Range, across the valley of the south-flowing Kaoping River. The range has major elevations between . The main peak, Data Mountain (大塔山), towers . Below the western foothills of the ranges, such as the Hsinchu Hills and the Miaoli Hills, lie raised terraces formed of material eroded from the ranges. These include the Linkou Plateau, the Taoyuan Plateau and the Dadu Plateau. About 23% of Taiwan's land area consists of fertile alluvial plains and basins watered by rivers running from the eastern mountains. Over half of this land lies in the Chianan Plain in southwest Taiwan, with lesser areas in the Pingtung Plain, Taichung Basin and Taipei Basin. The only sizable plain on the east coast is the Yilan Plain in the northeast. Climate The island of Taiwan lies across the Tropic of Cancer, and its climate is influenced by the East Asian Monsoon. Northern Taiwan has a humid subtropical climate, with substantial seasonal variation of temperatures, while parts of central and most of southern Taiwan have a tropical monsoon climate where seasonal temperature variations are less noticeable, with temperatures typically varying from warm to hot. During the winter (November to March), the northeast experiences steady rain, while the central and southern parts of the island are mostly sunny. The summer monsoon (from May to October) accounts for 90% of the annual precipitation in the south, but only 60% in the north. The average rainfall is approximately 2,600 mm per year. Typhoons are most likely to strike between July and October, with on average about four direct hits per