India receives most rains from the southwest monsoon.

The southwest monsoon is the primary rainy season in India, bringing the majority of the country's annual rainfall. It is characterized by the movement of moist air from the Indian Ocean towards the Indian subcontinent, resulting in widespread precipitation across the region. This monsoon season typically occurs from June to September and accounts for about 70-90% of India's total annual rainfall.

Factors influencing the southwest monsoon:
1. Geographical location: India's geographical location plays a significant role in the onset and intensity of the southwest monsoon. The presence of the Western Ghats along the western coast and the Himalayas in the north acts as a barrier, forcing the moist air to rise and condense, leading to heavy rainfall.

2. Monsoon winds: The southwest monsoon is driven by the seasonal reversal of wind patterns. During summer, the landmass of the Indian subcontinent heats up faster than the surrounding oceans, creating a low-pressure area. This draws in moisture-laden winds from the southwest, resulting in rainfall.

3. Inter-tropical convergence zone (ITCZ): The ITCZ is a belt of low pressure near the equator where the northeast and southeast trade winds converge. During the summer months, the ITCZ shifts towards the northern hemisphere, bringing the southwest monsoon rains to India.

4. El Niño and La Niña: The El Niño-Southern Oscillation (ENSO) phenomenon in the Pacific Ocean can affect the strength of the southwest monsoon. El Niño events often result in reduced rainfall, while La Niña events enhance monsoon rainfall.

5. Topography: India's diverse topography, including coastal areas, plains, plateaus, and mountains, influences the distribution and intensity of rainfall during the monsoon season. The Western Ghats, for example, receive heavy rainfall due to their perpendicular alignment to the monsoon winds.

Other rainfall contributors:
While the southwest monsoon is the primary source of rainfall in India, other factors can also contribute to precipitation, especially in certain regions. These include:

- The retreating monsoon: After the southwest monsoon, the northeast monsoon occurs in the months of October and November. It brings rainfall to parts of southern India, particularly the eastern coast.

- Tropical cyclones: India's coastal regions, especially the eastern coast, can experience heavy rainfall due to tropical cyclones originating in the Bay of Bengal. These cyclones bring intense rainfall and strong winds.

Overall, the southwest monsoon is responsible for the majority of India's rainfall, making it a crucial factor in the country's agriculture, water resources, and overall ecosystem.