The word ‘Monsoon’ is derived from the Arabic word ‘Mausim’ Monsoon is flow pattern of the general atmosphere circulation over a wide geographical area, in which there is a clearly dominant wind in one direction in every port of the region concerned, but in which this prevailing direction is reversed (or almost reversed) from winter to summer and from summer to winter.”
The monsoons are the key to understand the climate of India. Locational and physiographic factors have greatly influenced the climatic characteristics of the country. Though its considerable portion belongs to the sub-tropical zone as a whole, it shares the characteristics of tropical monsoon climate, mainly because of the Himalayas, functioning as an effective meteorological barrier.
The highest rainfall recorded at Cherrapunji (more than 1000 cm) is the result of the inter play of the vigorous sweep of the monsoon currents and the funnel-shaped alignment of the adjoining ranges. The occasional sweeps of the westerly disturbances after having transcended the northwestern range are oriented to the Great Plains and the northern margins of the peninsular foreland.
It may however be noted that the Himalayas themselves represent the climatic mosaic with tropical to alpine or polar variations. Marine influences are also significant due to the peninsular projections of the landmass into the Indian Ocean. India is a par excellence, a tropical monsoon country.