The winter rainfall in the northern plains of India is predominantly caused by Western Disturbances. These are temperate cyclones that originate over the Mediterranean Sea and travel eastward across Iran, Afghanistan, and Pakistan, bringing moisture to the Indian subcontinent during the winter months (December to February). They cause light to moderate rainfall in the plains and snowfall in the mountainous regions. Southwest Monsoons bring summer rainfall, Tropical Cyclones affect coastal regions primarily, and North-East Monsoons bring winter rainfall mainly to the southeastern coast of India, like Tamil Nadu, not the northern plains.