Short Description of the Climate of Ethiopia

In Ethiopia, the pattern and character of rainfall varies in different parts of the country. There are some regions, which experience three seasons (tri-modal type) with two rainfall peaks (where one peak is more prominent than the other), while some regions have four seasons with two distinct rainfall peaks (bi-modal type). There are still some regions, which have two seasons with single rainfall peak (mono-modal type). Click here for the figure.

Areas under region A are characterized by three distinct seasons and are locally known as Bega (October to January), Belg (February to May) and Kiremt (June to September). The rainfall pattern in region A has two distinct peaks during a year.

Areas under region C over the southern and southeastern parts of the country are characterized by two distinct rainfall peaks with dry season in between, where the first wet season is from March to May and the second is from September to November.

Areas demarcated by region B are characterized by single rainfall peak during a year, where two distinct seasons, one being wet and the other dry are encountered. Mean monthly rainfall pattern shows that the southwestern, western and northwestern parts of the country are under their wet season during February/March to October/November, April/May to October/ November and June to September, respectively.

The National Meteorological Services Agency, considering the dominant regional atmospheric circulations, and the rainfall patterns across the three major rainfall regimes over the country uses the following seasonal classification for operational monitoring and forecasting of the weather over the country.

October to January (Bega) :- Predominantly called Bega(dry season)over areas in Region A, also part of the long dry season over northwestern parts of the country of region B, where as over the western and southwestern parts of the country of region B, denotes the time when the long rainfall season comes to an end to be followed by a medium to short dry season during the same period. During the first half of this season, south and southeastern parts of the country of region C get their short rain season due to the southward retreating Inter Tropical Convergence Zone. Year to year variabilities of the weather during this season are largely related to intensities of the occurrences of west-ward moving depressions over the Arabian Sea, intensities of the Siberian High pressure system and its extension and the Saharan high pressure system which may affect the variabilities in the cloudiness and minimum temperature values over the central, eastern, western, southwestern and northwestern parts of the country. Northeastern parts of the country and adjoining areas can sometimes get some rain during January due to the east ward moving northern hemisphere mid latitude systems coupled with the Red Sea convergence Zone. Moreover Global tele-connection patterns such as the ENSO also can have influences on abnormal weather conditions such as un-seasonal rainfall activities over areas where this season is considered normally as a dry season.

February to May (Belg): - Predominantly called Belg or Small rainy season over areas in region A, where as over the southwestern parts of the country of region B it denotes the start of the long rainy season. Over the western parts of the country of region B also the rainy season starts during March/April. However over the northwestern parts of the country of region B, this season is predominantly dry except for the month of May. Southern and southeastern parts of the country of region C are expected to get their long rainy season during this time starting in March and peaking in April.

June to September (Kiremt ):- Predominantly called Kiremt season which is considered as the main rainy season in which about 85% to 95% of the food crops of the country are produced. The magnitude of rainfall is higher as compared to the other seasons for many parts of the country. It is to be noted that this rainfall season is not experienced over the southern and the southeastern lowlands of the country due to divergence field of the wind originating from the Indian Ocean over these areas. Thus, we have to note that there are variations in the timing of rainfall seasons and rainfall peaks over different parts of the country.

Click at Bega , Belg , Kiremt and Annual for the corresponding mean rainfall maps.