The Poso is a river of Central Sulawesi on Sulawesi island, Indonesia, about 1600 km northeast of the capital Jakarta.

[3] The river flows in the central area of Sulawesi with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification).

[4] The annual average temperature in the area is 22 °C (72 °F).

The warmest month is October, when the average temperature is around 23 °C (73 °F), and the coldest is January, at 20 °C (68 °F).

[5] The average annual rainfall is 2,715 millimeters (106.9 inches).