I forget where I picked this up, but it's very effective in these circumstances, and not just with my wife: "You may be right, I'll think about it." Then just get on with whatever you were doing.
With Diwali being on 4 November this year they are asking for a leap of faith if they expect Indians to book to come given the justifiable expectation that a flip-flop will happen between now and 1 November.
Even if they did consider a visit, Indians are a fun-loving people and a week watching the tide come in and out is hardly the definition of a memorable Diwali.
Anyone thinking of a vacation in Thailand this year or early next should go to see a neurologist.