The river flows in the central area of Sumatra with predominantly tropical rainforest climate (designated as Af in the Köppen–Geiger climate classification).[3] The annual average temperature in the area is 23 °C. The warmest month is September, when the average temperature is around 24 °C, and the coldest is January, at 21 °C.[4] The average annual rainfall is 3023 mm. The wettest month is November, with an average of 444 mm rainfall, and the driest is June, with 124 mm rainfall.[5]
