Question

Why does Chennai receive less rainfall than kochi even though it has more rainy months?

Answer 1

India has 2 monsoon seasons, the Summer monsoon and winter monsoon. The Summer monsoon originate in an area of high pressure in the southern Indian Ocean and blow in the S-W to N-E direction towards the low pressure land area. Hence as the wind blows from sea to land, the water content in the monsoon wind is high. The winter monsoon (N-E monsoon) blow from land to sea and hence it is dry. Over it's course, a part blows over the Bay of Bengal where they gather moisture and cause rainfall along the Coromandel coast where Chennai lies. Hence the rains from summer monsoon js heavier as the sea mass over which it blows is larger.

Monsoon season in Kochi is mainly from June to September brought by the South Western winds originated from the Arabian sea. As Kochi lies at the windward side of the S-W monsoon winds, it experiences heavy rainfall during this season. Kochi also experience lighter rainfall from October to December from the North Eastern monsoon winds as it lies at the leeward side of the North Eastern monsoon winds.

Chennai lies at the Windward side of north eastern monsoon hence the area receive most rain from the N-E monsoon which have comparatively lesser water content, from October to December. Chennai also get rain from the S-W monsoon (April - October) which is lighter due to being located at the leeward side of S-W monsoon winds.

Source : wikipedia, ncert text book and imd chennai