1985–86 South-West Indian Ocean cyclone season

The 1985–86 South-West Indian Ocean cyclone season was the first in which the Météo-France office (MFR) on Réunion tracked cyclones as far east as 90° E in Indian Ocean, south of the equator. Previously, the agency's area of responsibility was limited to 80° E. It was an active season with twelve named storms, of which five strengthened into tropical cyclone with 10 minute sustained winds of at least 120 km/h (75 mph). The first named storm was Tropical Storm Alifredy, which originated in the Mozambique Channel in late December and moved across Madagascar. However, the unofficial Joint Typhoon Warning Center (JTWC) tracked a short-lived storm in September.

Most of the activity occurred in 1986, with four storms in January, three of which briefly existed simultaneously on January 10. The first of these three, Tropical Storm Berobia, struck eastern Mozambique. Tropical Storm Costa was a series of three tropical depressions within the same broader system that persisted for 12 days, bringing gusty winds and rainfall to the Mascarene Islands. The strongest storm of the season, Erinesta, formed in late January and struck the tiny Tromelin Island, decimating the native rabbit population. Erinesta later produced 1,643 mm (64.7 in) of rainfall in the mountainous peaks of Réunion, one of the highest 24‑hour rainfall totals at the time at Cilaos. Two other storms in February – Filomena and Gista – moved southward for their durations and did not significantly impact land. In March, Cyclone Honorinina killed 99 people and caused $150 million (1986 USD) in damage when it struck eastern Madagascar. There were two other storms in March, Iarima and Jefotra, the latter of which brushed Rodrigues island with gusty winds. The final two storms of the season, Krisostoma and Lila, entered from the Australian basin in April and May, respectively, with Lila exiting the basin to end the season on May 10.