The river flows in the southern area of Sumatra which has a predominantly tropical rainforest climate (designated as Af in the Köppen–Geiger climate classification).[3] The annual average temperature in the area is 24 °C. The warmest month is October, with the average temperature of 26 °C, and the coldest is January, at 22 °C.[4] The average annual rainfall is 2,902 mm. The wettest month is November, with an average of 435 mm rainfall, and the driest is August, with 83 mm rainfall.[5]
