The climate of Idukki is typically tropical with a significant amount of rainfall throughout the year. The region experiences a monsoon season from June to September, which is the primary source of precipitation in the area. 

During the monsoon season, the humidity levels are high, and the region experiences heavy rainfall, often resulting in landslides and flooding while January is the coolest and May is the warmest months in the regio. 

During the winter months from December to February, the climate is generally dry and pleasant, with a slight drop in temperature. The period between October and November is the post-monsoon season when the region experiences light rainfall and a drop in temperature.

However, due to the hilly terrain, the climate can vary significantly within short distances, with some areas experiencing more rainfall than others.