The 2011-12 South-West Indian Ocean cyclone season was an annual event of tropical cyclone formation. It started on November 15, 2011 and ended on April 30, 2012. For Mauritius and the Seychelles, the season continued until May 15. These dates conventionally delimit the period of each year when most tropical cyclones form in the basin, which is west of 90°E and south of the Equator. Tropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion.