Where can I go windsurfing or snorkeling in July in southern India?

I'm visiting an event in Madurai, Tamil Nadu, India in July this year and I'm wondering whether I could add on a week at the beach afterwards. I usually go windsurfing and/or snorkeling when I stay at the beach.

Now I've read that July is monsoon season, but I've also read that it depends very much on the location. I don't mind a short heavy downpour every other day or high humidity, but I want to avoid constant rain. I've also read that there is no wrong time of year to visit Sri Lanka since one coast is always dry no matter which direction the rain comes from, so if southern India isn't a good option, I'd be happy to get recommendations for Sri Lanka as well.

So the question is: Where in southern India or Sri Lanka could I go for a 1-week stay at the beach in the second half of July with reasonably dry weather and the opportunity to go windsurfing and/or snorkeling?