The river flows in the central area of Sulawesi island with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification). The annual average temperature in the area is 23 °C. The warmest month is October, when the average temperature is around 24 °C, and the coldest is April, at 22 °C. The average annual rainfall is 2929 mm. The wettest month is April, with an average of 341 mm rainfall, and the driest is September, with 79 mm rainfall.