The State of Karnataka lies in the south of India and covers an area of 191,976 square kilometers, or 5.83% of the area of India. It is the eighth largest Indian state by area with over 61 million inhabitants. The two main river systems of the state are the Krishna and its tributaries (Bhima, Ghataprabha, Vedavathi, Malaprabha, and Tungabhadra) in the north, and the Cauvery and its tributaries (Hemavati, Shimsha, Arkavathi, Lakshmana Thirtha, and Kabini). Both these rivers flow eastward into the Bay of Bengal.

The State comprises three meteorological zones namely (a) Coastal Karnataka, (b) North Interior Karnataka and (c) South Interior Karnataka. Of these, the coastal zone receives the heaviest rainfall with an average rainfall of about 3,638.5 mm (143 in) per annum, far in excess of the state average of 1,139 mm (45 in). The annual rainfall in the state varies roughly from 50 to 350 cm. The highest recorded temperature was 45.6 °C (114 °F) at Raichur and the lowest recorded temperature was 2.8 °C (37 °F) at Bidar.

A table which gives the details about the River Systems in Karnataka