In accordance with geography, Tamil Nadu is an area in India, located on it's the eastern coast.
☆ We already know that south India receives rainfall from the south west monsoons. A majority part of Tamil Nadu state is underneath a climatic classification called Köppen. Since these southwest monsoons originate from the Arabian Sea, it gets obstructed by the Western Ghats.
The remaing smaller part of the Tamil Nadu state falls underneath the humid subtropical climatic region.
☆ In addition to this, Tamil Nadu receives some rain from north east and retreating monsoons during winter season. With respect to many low pressure systems, they are developed in the Bay of Bengal during the monsoon time and move towards the east coast of Tamil Nadu thus causing heavy rainfall.
Hence, the coast of Tamil Nadu in India receives winter rainfall, causing the increment in the growth of crops there.