Rainfall is higher on the southern and eastern slopes facing the Indian Ocean, and lower in the mountains' rain shadow to the north and west.

[3] The Rubeho Mountains, along with the others in the Eastern Arc, are made up of ancient crystalline Precambrian rocks that were uplifted over millions of years along fault lines.

The long-term persistence of a humid climate and the isolation of each mountain range has led to a great deal of endemism, and a very diverse flora and fauna.

[1] Tree species in the montane evergreen forests include Agarista salicifolia, Aphloia theiformis, Bridelia micrantha, Catha edulis, Diospyros whyteana, Halleria lucida, Macaranga kilimandscharica, Maesa lanceolata, Maytenus acuminata, Nuxia congesta, Parinari excelsa, Polyscias fulva, Rapanea melanophloeos, and Xymalos monospora.

[6] On the western slopes of the main plateau, Macaranga kilimandscharica is the predominant tree, forming a 10-15-meter canopy in dry montane forests in valleys at 1,600–1,700 meters elevation.

Mangalisa is a separate mountain block west of the main plateau, north of the Great Ruaha River.

At Kilosa the Central Railway's Mikumi line branches south through the Mkata Plain east of the mountains.