The whole Nile Basin is broadly categorized  into Mediterranean, arid, semiarid, subtropical and tropical climatic regions. “The areas around the Equatorial lakes, south-western Ethiopia and the southern parts of Sudan have a tropical climate characterized by well-distributed rainfall and little variation in mean temperature depending on the locality and altitude. The climate gradually changes as one goes northwards progressing through subtropical, semiarid to a desert-type climate in northern Sudan and Egypt.” (UNEP, 2013)


Rainfall in the Nile Basin shows high spatio-temporal  variability. It is influenced by the forward and retreat movement of the Inter-Tropical Convergence Zone (ITCZ) (Camberlin, 2009; Sutcliffe and Parks, 1999). Precipitation generally increases from north to south and with elevation.
Areas receives less than 100mm rainfall per year, which experiences hyper-arid climate, is about  28 per cent of the basin. On the other hand, about 34 per cent of the basin experience sub-humid conditions and receives between 700 and 1300 mm of rain. Furthermore the southwestern part of South Sudan, the Equatorial Lake region and the Ethiopian highlands receive more than 1000 mm of rainfall per year (Camberlin, 2009).


References and further reading:

Conway, D. (2000) The climate and hydrology of the Upper Blue Nile, Ethiopia, Geographical Journal, 166, 49–62.

Camberlin, P. (2009) Nile Basin Climates, The Nile: Origin, Environments, Limnology and Human Use.

NBI (2012) State of the River Nile Basin Report, Nile Basin Initiative (NBI) Publishing, Entebbe, Uganda.

Sutcliffe, J., Parks, Y. P. (1999) The Hydrology of the Nile, IAHS Special Publication no. 5, IAHS Press, Institute of Hydrology, Wallingford, Oxfordshire OX10 8BB, UK, p. 33, and 57–87, 1999.

Wolman, M. G., Giegengack, R. F. (2008) The Nile River: Geology, Hydrology, Hydraulic Society, Large Rivers. John Wiley & Sons, Ltd, 471–490. 

UNEP (2013) Adaptation to Climate-change Induced Water Stress in the Nile Basin: A Vulnerability Assessment Report, Division of Early Warning and Assessment (DEWA), United Nations Environment Programme (UNEP), Nairobi, Kenya.

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