The atmospheric conditions in the Gina River catchment show following characteristics:

• The annual average temperature in the Gina River catchment totals 14°C.
• The annual precipitation measured at 2680 m a.s.l. (Chencha weather station) is 1350 mm.
• Most of the rain falls in two rainy seasons, with dry conditions in between. The first one from March to April is short (belg) and a subsequent long rainy season from July to Octobre (krempt). The seaonality of rainfall is caused by the migration of the Inner-Tropical Convergence Zone. The dry conditions in the Gina River catchment are due to the impact of the north-east trade winds carrying dry air.
• The drainage basin shows a hypsographic differentiation: rainfall increases and temperature decreases with higher elevation (Beck et al. 2004).