2018–19 South-West Indian Ocean cyclone season

The 2018–19 South-West Indian Ocean cyclone season was the costliest and the most active season ever recorded. Additionally, it is also the deadliest cyclone season recorded in the South-West Indian Ocean, surpassing the 1891–92 season in which the 1892 Mauritius cyclone devastated the island of Mauritius, and is mainly due to Cyclone Idai. The 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 15 November 2018, and ended on 30 April 2019, except for Mauritius and the Seychelles, which it ended on 15 May 2019. 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.

The season set a new record of nine intense tropical cyclones, the largest number since the start of reliable satellite coverage in 1967, surpassing the 2006–07 season. Beginning the season early, Moderate Tropical Storm 01 formed during September 2018. Two other systems formed prior to the official start of the season during November—the first intense tropical cyclone and the first named storm, Alcide, and Severe Tropical Storm Bouchra. A pair of intense tropical cyclones—Cilida and Kenanga—persisted in December. In January 2019, Desmond caused damages in Mozambique, and shortly thereafter, Eketsang passed by Madagascar, producing heavy rain and landslides that killed 27. Onto the next month, Funani and Gelena threatened Rodrigues, with the latter disrupting its electricity and causing US$1 million in damages.

The most active and destructive month was March. Haleh remained near the centre of the basin, bringing no impact. Cyclone Idai made two landfalls in Mozambique as a tropical depression and intense tropical cyclone, causing at least 1,593 deaths and leaving at least 2,262 people missing, and causing US$3.3 billion in damages in Mozambique, Zimbabwe, Malawi, and Madagascar. Savannah entered the basin in the middle of the month. Joaninha became the second cyclone of 2019 to strike Rodrigues, destroying the island's power grid. In April, Kenneth became the strongest storm of the season, with maximum sustained winds of 215 km/h (130 mph); the storm killed at least 7 people in Comoros and made landfall in Mozambique, causing at least 45 deaths and overall damage of US$345 million. Lorna remained over the eastern portion of the basin, concluding the season after it dissipated on 29 April.