Sudan is a transition zone between the Sahelian dry desert climate and the dense humid equatorial rainforest. Average annual temperatures vary between 23 and 29 degrees. Temperatures in the coldest months are above 20 degrees Celsius and over 30 degrees Celsius in the hottest months. Daily temperature fluctuations are up to 10-15 degrees. The summer monsoon brings rain from the equator. Precipitation ranges from 100-200 mm in the north to 1,500-2,000 mm in the south. During the dry winter season, the hot and dry Harmattan northeasterly wind from the Sahara.