Үнді мұхитындағы тропикалық дауылдар мен олардың белсенді аймақтары

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In the Indian Ocean north of the equator, tropical cyclones can form throughout the year on either side of the Indian subcontinent, although most frequently between April and June, and between October and December.

The North Indian Ocean is the least active official basin, contributing only seven percent of the world's tropical cyclones. However the basin has produced some of the deadliest cyclones in the world, since they strike over very densely populated areas. The Regional Specialized Meteorological Centre (RSMC) is the India Meteorological Department (IMD) and it is responsible to monitor the basin, issues warning and name the storms. The basin is divided into two sub basins the Bay of Bengal and the Arabian Sea. The Bay of Bengal, located in the northeast of the Indian Ocean. The basin is abbreviated BOB by the India Meteorological Department (IMD). The United States's Joint Typhoon Warning Center unofficially designates as B to classify storms formed in the Bay of Bengal. The Bay of Bengal's coast is shared among India, Bangladesh, Myanmar, Sri Lanka and western part of Thailand. This sub basin is the most active and produces some of the deadliest cyclones of all time. The most intense cyclone in the bay was the 1999 Odisha cyclone. The Arabian Sea is a sea located in the northwest of the Indian Ocean. Tropical cyclones in the basin are abbreviated ARB by the India Meteorological Department (IMD). The Arabian Sea's coast is shared among India, Yemen, Oman, UAE, Iran, Pakistan, Sri Lanka, Maldives and Somalia. Monsoons are characteristic of the Arabian Sea and responsible for the yearly cycling of its waters. In summer, strong winds blow from the southwest to the northeast, bringing rain to the Indian subcontinent. Cyclones are rare in the Arabian Sea, but the basin can produce strong tropical cyclones.

The systematic scientific studies of tropical systems in the Bay of Bengal and Arabian Sea was started during the 19th century by Henry Piddington. Piddington utilised meteorological logs of vessels that navigated the seas and published a series of memoirs, in the Journal of the Asiatic Society of Bengal between 1839 and 1858. During 2015 a modification to the intensity scale took place, with the IMD and WMO calling a system with 3 minute maximum sustained wind speeds between and an extremely severe cyclonic storm. A study analysing the spring season of tropical cyclones in the Bay of Bengal found increases in both pre monsoon precipitation and tropical cyclone intensity as a result of enhanced large scale monsoon circulation after 1979. The deepened monsoon trough in the Bay of Bengal not only affects cyclone frequency and timing, but also acts to direct more cyclones towards Myanmar. Increased anthropogenic aerosols likely contributed to such a regional climate change.

On average only five to six tropical cyclones form in the basin each year. Tropical cyclones form in the months of March to June and October to December, with peaks at May and November. Most of these storms form in the Bay of Bengal: either in the southeastern Bay of Bengal, in the Andaman Sea, or as a remnant of a typhoon from the South China Sea. There are many tropical cyclones in the West Pacific; this may be another reason for increased tropical cyclogenesis in the Bay, as it shares a fair portion of the increased quota of ACE. Meanwhile, the storms in the Arabian Sea mostly form over south eastern part of the Arabian Sea or a remnant of a tropical cyclone from the Bay of Bengal, however the frequency of cyclogenesis in the Arabian Sea is generally less, due to cooler sea surface temperature and high wind shear. Very few tropical cyclones develop in the months of June to September (Monsoon months) because of high vertical wind shear. These storms form and peak as depressions or deep depressions before making landfall in Odisha or West Bengal. Another reason is the low life span in the sea which also avoids the intensification of these low pressure systems.

Intensification probability is maximum in the month of April, May and November in case of a depression becoming a cyclonic storm and severe cyclonic storm. More than half of the depressions intensify into a storm and a quarter intensify into a cyclone in these months.