There are three main climatic zones in Mali; ranging from the Saharan zone in the north, through the semi-arid Sahelian zone around the Niger (marking the transition between the desert and the raised savannah), through to the 'Sudanese' climate in the south. Temperatures average between 24° and 32°C in the south, and rise to the north. The annual precipitation varies from 1,120 mm in Bamako to less than 130 mm in the Sahara region.