Trans-Kalahari Corridor South African border at Pioneer Gate/Skilpadshek. In South Africa it follows the N4 through Rustenburg to Pretoria. The route Walvis Bay–Windhoek–Lobatse–Pretoria–Maputo is route number 40 in the Southern African Development Community Regional Trunk Road Network. Trans-Kalahari Corridor The Trans-Kalahari Corridor is a paved highway corridor that provides a direct route from Walvis Bay and Windhoek in central Namibia, through Botswana, to Johannesburg and Pretoria in Gauteng province in South Africa. It initially cost approximately 850 million Namibian dollars (US$115 million) and was officially opened in 1998. The corridor also includes railway lines from Walvis Bay as far as Gobabis in
Kalahari Desert and South Africa, and encroaching into parts of Angola, Zambia and Zimbabwe. North and east, approximately where the dry forests, savannahs and salt lakes prevail, the climate is sub-humid rather than semi-arid. South and west, where the vegetation is predominantly xeric savanna or even a semi-desert, the climate is "Kalaharian" semi-arid. The Kalaharian climate is subtropical (average annual temperature greater than or equal to 18 °C, at peaks reaching 40 °C and above, with mean monthly temperature of the coldest month strictly below 18 °C), and is semi-arid with the dry season during the "cold" season, the coldest six months