Orange River Basin Rainfall in Average Year

There is a defined zonal pattern across the basin with high rainfall occurring in the mountain region of the eastern basin, lower rainfall in the grass land savannah of the middle reaches and finally very low rainfall (can be as low as 50mm/yr) in the desert conditions of the western basin. Rainfall is lowest in the dry winter months (June, July, August). In very dry years the river does not reach the sea, one cause of this is the evaporation potential is greatest in the lower arid reaches of the river system. The dams located upstream on the Orange River influence and reduce the flow of the lower Orange River and loss of wetlands at the river mouth is one consequence of this.

Average Total Rainfall (mm/yr)

Bargraph referencing the colours on the rainfall maps.

Other Orange Maps

Orange Rainfall Maps