How does the southwest monsoon affect Karnataka’s climate?

The southwest monsoon, occurring from June through September, is the primary driver of Karnataka’s climate and accounts for the majority of the state’s annual precipitation.1

The Western Ghats play a critical role in this process by acting as a barrier to moisture-laden winds blowing from the Arabian Sea. As these winds encounter the steep seaward slopes of the mountains, they are forced upward, resulting in heavy rainfall. Consequently, the wettest parts of the coastal plain can receive nearly 160 inches (4,000 mm) of rain annually.2341

Conversely, the Western Ghats create a rain-shadow effect that significantly influences the interior of the state. As the clouds and winds roll over the mountain barrier, they lose much of their moisture, leaving the inland Deccan plateau much drier. As a result, annual precipitation in the drier portions of the Maidan region can be as low as 20 inches (500 mm).231