The river flows in the northern area of Sumatra with predominantly
tropical rainforest climate (designated as
Af in the Köppen-Geiger climate classification). The annual average temperature in the area is 24 °C. The warmest month is June, when the average temperature is around 26 °C, and the coldest is January, at 23 °C. The average annual rainfall is 2950 mm. The wettest month is November, with an average of 381 mm rainfall, and the driest is June, with 117 mm rainfall. ==See also==