Tamil Nadu essentially enjoys tropical weather throughout the year hence there?s scarcely much temperature variation, as you?d notice in North India. From March to October, the humidity level soars, and even the mercury level remains 38�C on average. Post monsoon season in Tamil Nadu in November, the climate of Tamil Nadu begins to get colder and remains cool till the end of March, making it the best time to visit Tamil Nadu, especially for sightseeing and temple tours.