Question

The winter rain in Chennai is caused by ___________.
(A) South-West Monsoons
(B) North-East Monsoons
(C) Intense Land and Sea Breezes
(D) Cyclonic winds in the Bay of Bengal

Answer 1

Hint: The climate of Tamil Nadu, India, except during the monsoon seasons, is generally tropical and has reasonably hot temperatures during the year.

Complete step by step answer: The majority of Tamil Nadu comes under Tropical savanna climate under the Koppen climate classification and a smaller portion of the state falls under Humid subtropical climate; the climate of the state varies from dry sub-humid to semi-arid. The summer in Tamil Nadu lasts during March, April, and May and is characterized by extreme heat and scant rainfall in the state. The climate in the cold of winter weather is pleasant. The state has three distinct rainfall periods: advanced rainfall; rainfall from tropical cyclones during the Retreat of Monsoons (October-November) emerging in the vicinity of the Andaman Islands; and the North-East monsoon during the months of October-December, with dominant northeast monsoon winds emerging from the western disturbances over the Bay of Bengal. From February to early June, the dry season takes place.
During the monsoon season, Tamil Nadu gets rain because of the southwest trade winds that blow to the northern hemisphere. Due to the northeast trade winds, Tamil Nadu receives rainfall in the winter season. The state's average annual precipitation is around 907 (LPA 1950-2019) mm (37.2 in), 48 percent of which is through the North-East monsoon, and 32 percent through the South-West monsoon. Since the state relies entirely on rain to recharge its water supplies, monsoon failures lead to acute water scarcity and severe droughts.
Seven agro-climatic zones are classified in Tamil Nadu: north-east, north-west, west, south, high rainfall, high altitude hills, and the Cauvery Delta (the most fertile agricultural zone).
Chennai is situated on India's eastern coast. Usually, South India receives rainfall from the southwestern monsoons. But the Western Ghats are blocking these South West Monsoons from the Arabian Sea. Thus, during the winter season, Chennai receives much of its rain from the north-east and receding monsoons. Also, during this time, several low-pressure systems formed in the Bay of Bengal and moved to the east coast of Tamil Nadu, causing heavy rainfall.

Thus, the answer is option B: North-East Monsoons

Note: Chennai received 1,049 mm (41.3 in) of rainfall in November during the 2015 South Indian floods (most affected districts: Chennai, Kanchipuram, and Cuddalore), the highest recorded since November 1918, when 1,088 mm (42.8 in) of rainfall was reported. The flooding was described as the worst in a century in Chennai.