Tamil Nadu has a tropical climate. From March to September the humidity level will be high and the average temperature would be 38 degree C or higher. From middle of September to November you might experience rainfall ranging from mild to moderate. Certain parts of the state might receive heavy rainfall. November to February is the winter period in Tamil Nadu.
The best time to visit Tamil Nadu is from November to March. All the tourist attractions would be at the prime beauty and the climate would be mild for sightseeing and other activities. Due to recent rainfall, all water bodies would be rich with water and flora will be flourishing. Most of the tourist activities would be available only during this season like boating, hill station trekking and others. November to January is the right season to visit any wildlife sanctuary. You can find animals with their cubs or migration birds only during this season. But, most of the sanctuary would be open throughout the year. If you are visiting in this season, you should not miss Pongal (Jan 15-Jan 17), a regional harvest celebration. In certain villages, you can also find bull fights during this celebration.
March to May is the hot summer season. It is the lean tourist season in this state. You can find better deals in accommodation, ticket and others during this season. Yet, if you are visiting in this period, you would not be disappointed. Most of the interesting cultural events and celebrations would be occurring in this period like Chithirai festival, Ooty’s flower exhibition and others. Moreover, all hill stations in this state like Ooty, Kodaikanal, Conoor, Yercaud and others would be very scenic. If you are visiting India during the summer season, remember that dehydration is common in those who cannot handle hot temperatures. You can ease the travel by hiring air-conditioned transportation facilities or choosing cool places.
In the same tone; monsoon season should not be discarded too. The hill stations would be very romantic in the monsoon season. Mild showers would refresh the look of ancient monuments and other structures. The travel can be a little messy. If you do not mind getting wet occasionally, then monsoon season can be a delight too. Visit Mahabalipuram during a mild shower of rain to experience the real beauty of monsoon in Tamil Nadu. Diwali is an important festival during monsoon season. You can find children bursting crackers and fireworks throughout the day. If you are in Tamil Nadu during Diwali, find a rooftop to spend the evening watching many colours burst open in the sky.