The 2019–20 South-West Indian Ocean cyclone season was an above average season. This cyclone season was an event of the annual cycle of tropical cyclone and subtropical cyclone formation in the South-West Indian Ocean basin. It officially began on November 15, 2019, and ended on April 30, 2020, with the exception for Mauritius and the Seychelles, for which it ended on May 15, 2020. These dates conventionally delimit the period of each year when most tropical and subtropical cyclones form in the basin, which is west of 90°E and south of the Equator. Tropical and subtropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion.
Within the South-West Indian Ocean, tropical depressions and subtropical depressions that are judged to have 10-minute sustained wind speeds of 65 km/h (40 mph) by the Regional Specialized Meteorological Center on La Réunion Island, France (RSMC La Réunion) are usually assigned a name. However, it is the Sub-Regional Tropical Cyclone Advisory Centers in Mauritius and Madagascar who name the systems. The Sub-Regional Tropical Cyclone Advisory Center in Mauritius names a storm should it intensify into a moderate tropical storm between 55°E and 90°E. If instead a cyclone intensifies into a moderate tropical storm between 30°E and 55°E then the Sub-Regional Tropical Cyclone Advisory Center in Madagascar assigns the appropriate name to the storm. Beginning from the 2016–17 season, name lists within the South-West Indian Ocean will be rotated on a triennial basis. Storm names are only used once, so any storm name used this year will be removed from rotation and replaced with a new name for the 2022–23 season. The unused names are expected to be reused in the list for the 2022–23 season.