Regional Climate Messages: East Africa
There is considerable variation in rainfall patterns across the region with weak trends overall. Temperature trends are more consistent, a 1.5ºC – 2ºC increase per decade over the last 50 years. Future projections of temperature change show significant increases across the region. Future changes in precipitation are much more varied with potential for increases as well as decreases.
Daron, J.D. (2014)
This report provides a general overview of the regional climate in East Africa. A follow-up report that provides a specific focus on the climate of the semi-arid regions of East Africa is currently under development.
1.1 General overview
The climate across East Africa varies from arid conditions in the east to more humid conditions in the west. A semi-arid transect is found in the Sahel region in central and southern Sudan, as well as a north-south transect running through central Ethiopia, Kenya and Tanzania and pockets of arid and semi-arid conditions are found elsewhere, such as northeast Kenya. Other climatic zones are also present, including tropical rainforest conditions in the Lake Victoria region of southern Uganda. The primary factors affecting the climates experienced in East Africa include altitude, the proximity of the warm Indian Ocean, the migration of the Inter-Tropical Convergence Zone (ITCZ) and the location of dominant atmospheric high and low pressure systems.
The equator passes through Uganda, Kenya and southern Somalia. Therefore the northern parts of the region receives the majority of its rain during the boreal summer months (June to August) while the southern parts of the region receives the majority of its rain during the austral summer months (December to February). Regions closer to the equator typically have two rainy seasons with peaks in rainfall in or around April and October. These peaks are particularly pronounced in the more arid regions.
The highest temperatures are experienced in the drier regions towards the north and east. Particularly high temperatures are found in Eritrea and Djibouti where average summer temperatures exceed 30°C. The lowest temperatures are found in the high altitude regions of Ethiopia, Kenya and Tanzania, located in on the edges of the East African Rift Valley.