South Arcot and Ramanathapuram receive over 50 percent of their annual rainfall from which one of the following?

South Arcot (now Cuddalore and Villupuram districts) and Ramanathapuram are located along the Tamil Nadu coast, a region that remains relatively dry during the summer southwest monsoon [4]. This is because the Tamil Nadu coast lies parallel to the Bay of Bengal branch and in the rain-shadow area of the Arabian Sea branch [1]. Consequently, these districts rely heavily on the North-east monsoon (retreating monsoon) which occurs from October to December [2]. During this period, winds crossing the Bay of Bengal pick up moisture and cause torrential rainfall over the Tamil Nadu coast [2]. For the state of Tamil Nadu, the North-east monsoon is the primary rainy season, accounting for approximately 48% of its annual rainfall, with coastal districts like Ramanathapuram often receiving over 50% to 60% of their total annual precipitation during this specific window.

Sources

1. [1] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 4: Climate > Monsoon Winds of the Bay of Bengal > p. 37
2. [4] https://tnau.ac.in/tamil-nadu-agro-climatic-zones/
3. [2] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 4: Climate > Understanding the Monsoon > p. 34