The river flows in the central area of Java with predominantly tropical monsoon climate (designated as Am in the Köppen-Geiger climate classification).[4] The annual average temperature in the area is 25 °C. The warmest month is October, when the average temperature is around 28 °C, and the coldest is January, at 23 °C.[5] The average annual rainfall is 2845 mm. The wettest month is January, with an average of 527 mm rainfall, and the driest is September, with 35 mm rainfall.[6]