Mar 26, 2016· This area is an arid zone. North Interior Karnataka receives the least amount of rainfall in the state and the average annual rainfall is just 731 mm. South Interior Karnataka: This region spreads over the districts of Bangalore Rural, Bangalore Urban, Chitradurga, Chamrajnagar, Chikmagalur, Hassan, Kodagu, Kolar, Mysore, Shimoga and Tumkur.