Idukki is a high altitude district at an elevation of 1,200m. 97% of the area is occupied by rugged mountains and forest. Periyar, Thodupuzhayar and Thalayar Rivers flow through here.
The climate of the western part shows great variation from the eastern side of the district. The western part is a midland having moderate temperature throughout and eastern part is highland area and has a cold climate. Rains from both south-west and north-eat monsoon wet the place heavily.