Is there any  kerala festival in Monsoon ?

Yes of course . The most important one is
Upcoming Kerala Monsoon Festival,
World famous 62nd Nehru Trophy Boat Race 9th August 2014
Ecogreen Homestay promotes Nehru Trophy Boat Race 9th August 2014

Cochin - Athirapally- Alleppey Houseboat Tour - contact  +919961466495