<P> Additionally, one of the causes of rain must happen . In the case of the monsoon, the cause is primarily orographic, due to the presence of highlands in the path of the winds . Orographic barriers force wind to rise . Precipitation then occurs on the windward side of the highlands because of adiabatic cooling and condensation of the moist rising air . </P> <P> The unique geographic relief features of the Indian subcontinent come into play in allowing all of the above factors to occur simultaneously . The relevant features in explaining the monsoon mechanism are as follows: </P> <Ol> <Li> The presence of abundant water bodies around the subcontinent: the Arabian Sea, Bay of Bengal, and Indian Ocean . These help moisture accumulate in the winds during the hot season . </Li> <Li> The presence of abundant highlands like the Western Ghats and the Himalayas right across the path of the southwest monsoon winds . These are the main cause of the substantial orographic precipitation throughout the subcontinent . <Ol> <Li> The Western Ghats are the first highlands of India that the southwest monsoon winds encounter . The Western Ghats rise abruptly from the Western Coastal Plains of the subcontinent, making effective orographic barriers for the monsoon winds . </Li> <Li> The Himalayas play more than the role of orographic barriers for the monsoon . They also help confine it to the subcontinent . Without them, the southwest monsoon winds would blow right over the Indian subcontinent into Tibet, Afghanistan, and Russia without causing any rain . </Li> <Li> For the northeast monsoon, the highlands of the Eastern Ghats play the role of orographic barrier . </Li> </Ol> </Li> </Ol> <Li> The presence of abundant water bodies around the subcontinent: the Arabian Sea, Bay of Bengal, and Indian Ocean . These help moisture accumulate in the winds during the hot season . </Li>

When does north east monsoon blow in the land of kerala