On 26 August, the BoM reported that a tropical low had developed on a shear line about 1300 km (810 mi) to the northwest of Cocos Island.

[1] Over the next couple of days the depression gradually developed further before at 1800 UTC on 27 August, TCWC Perth estimated that it had become a tropical cyclone and named it Tony.

[1] During the next day, Tony moved into the South West Indian Ocean and weakened gradually before it dissipated during 31 August.

[1] Neither the Mauritius or Reunion meteorological services monitored Tony as a tropical cyclone while it was active, while it was not included in the JTWC's analysis of the season.

[9] For twelve days, Hyacinthe dropped torrential rainfall on Réunion; nearly all of the island received more than 1 m (3.3 ft) of precipitation.

The heaviest rainfall occurred through a process called orographic lift in the mountainous interior, leading to hundreds of landslides.

On March 13, the cyclone passed just east of Mauritius, producing wind gusts of 109 km/h (68 mph) and 65.7 mm (2.59 in) of rainfall.