These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.
The scope of this article is limited to the Indian Ocean in the Northern Hemisphere, east of the Horn of Africa and west of the Malay Peninsula.
There are two main seas in the North Indian Ocean — the Arabian Sea to the west of the Indian subcontinent, abbreviated ARB by the India Meteorological Department (IMD); and the Bay of Bengal to the east as BOB.
The official Regional Specialized Meteorological Centre in this basin is the IMD, while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories.
The names were selected by a new list from the Regional Specialized Meteorological Center in New Delhi by mid year of 2020.