in the centre, reaching in the north near Mbala. These plateau areas of northern Zambia have been categorised by the World Wildlife Fund as a large section of the Central Zambezian miombo woodlands ecoregion. Eastern Zambia shows great diversity. The Luangwa Valley splits the plateau in a curve north-east to south-west, extended west into the heart of the plateau by the deep valley of the Lunsemfwa River. Hills and mountains are found by the side of some sections of the valley, notably in its north-east the Nyika Plateau () on the Malawi border, which extend into Zambia as the Mafinga Hills, containing the country's highest point, Mafinga Central (). The Muchinga Mountains, the watershed between the Zambezi and Congo drainage basins, run parallel to the deep valley of the Luangwa River and form a sharp backdrop to its northern edge, although they are almost everywhere below . Their culminating peak Mumpu is at the western end and at is the highest point in Zambia away from the eastern border region. The border of the Congo Pedicle was drawn around this mountain. The southernmost headstream of the Congo River rises in Zambia and flows west through its northern area firstly as the Chambeshi and then, after the Bangweulu Swamps as the Luapula, which forms part of the border with the Democratic Republic of the Congo. The Luapula flows south then west before it turns north until it enters Lake Mweru. The lake's other major tributary is the Kalungwishi River, which flows into it from the east. The Luvua River drains Lake Mweru, flowing out of the northern end to the Lualaba River (Upper Congo River). Lake Tanganyika is the other major hydrographic feature that belongs to the Congo basin. Its south-eastern end receives water from the Kalambo River, which forms part of Zambia's border with Tanzania. This river has Africa's second highest uninterrupted waterfall, the Kalambo Falls. Climate Zambia is located on the plateau of Central Africa, between above sea level. The average elevation of gives the land a generally moderate climate. The climate of Zambia is tropical, modified by elevation. In the Köppen climate classification, most of the country is classified as humid subtropical or tropical wet and dry, with small stretches of semi-arid steppe climate in the south-west and along the Zambezi valley. There are two main seasons, the rainy season (November to April) corresponding to summer, and the