Help a sister out

Coming to Chennai for the first time in life. Please help me decide what should I take with me Is it going to be raining the next 3 months from now on? Should I take raincoat and bag cover or not? What about the weather? Sunscreen or Moisturizer? (i have oily skin) short skirts or modest ones? Sweaters or Summery dresses? Also could you please tell me some local phrases for auto wala interact interactions? Should I also keep my pepper spray? (i dont know if they allow it on flights tho) Any other tips?