Weather will likely play an important role when you plan your trip to Idukki, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and March, with an average temperature of 26°C, while the coldest months are January and February, with an average of 23°C. The rainiest months in Idukki are October, November, August and December, with each month seeing an average of 183 mm of rainfall.