2019–20 South-West Indian Ocean cyclone season (Olo72)

The 2019-20 Southwest Indian Ocean cyclone season was the most active since the start of reliable satellite coverage in 1967, with 19 named storms including one named tropical depression. Activity lasted from mid-November, when Moderate Tropical Storm Ambali formed, until mid-April when Tropical Depression 23 became a remnant low.

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 were monitored by the Regional Specialised Meteorological Centre in Réunion, though the Joint Typhoon Warning Center issued unofficial advisories.

Season outlook
On November 4, the Mauritius Meteorological Services (MMS) released their summer 2019–20 outlook. It is expected that twelve to fifteen cyclones will form in the Southwest Indian Ocean throughout the season from November through the first half of May. MMS also indicated that the region of Diego Garcia would be a center of focus for cyclone formation.

Storm names
Within the South-West Indian Ocean, tropical depressions and subtropical depressions that are judged to have 10-minute sustained windspeeds 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 2019–20 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 2023–24 season.