The river flows in the central north area of Java with predominantly tropical monsoon climate (designated as Am in the Köppen-Geiger climate classification).[5] The annual average temperature in the area is 25 °C. The warmest month is September, when the average temperature is around 28 °C, and the coldest is December, at 24 °C.[6] The average annual rainfall is 2702 mm. The wettest month is December, with an average of 423 mm rainfall, and the driest is September, with 26 mm rainfall.[7]