During the season despite positive values of the Southern Oscillation Index being recorded throughout the season, there was an unusual distribution of tropical cyclones with five developing between 180° and 140°W. This unusual distribution of tropical cyclones was attributed to the relatively rapid development of an active South Pacific Convergence Zone over an area of cooler than normal sea surface temperatures during January and February 1989.
On January 1, TCWC Nadi reported that a shallow and ill defined tropical depression, had developed about 400 km (250 mi) to the east of the Samoan Islands. Over the next few days the depression moved towards the southwest, while gradually developing further, before slightly weakening on January 3, as convection surrounding the system had decreased as it started to recurve and move towards the southeast. Over the next couple of days satellite imagery showed that the system was re-intensifying, before at 1800 UTC on January 5, TCWC Nadi reported that the depression had developed into a tropical cyclone and named it Fili, while it was at its peak intensity of 95 km/h (60 mph). After the cyclone was named it continued to move south-eastwards, before it was last noted to the southeast of the Cook Islands, on January 8 by TCWC Wellington.
On February 21, the Tahiti Meteorological office started to monitor a tropical depression that had developed on February 19 near the Pitcairn Islands. During February 21, the depression gradually developed further as it moved towards the west-southwest. Later that day it was named Hinano by Tahiti, after it had developed into a severe tropical storm and had become equivalent to a category two tropical cyclone on the Australian tropical cyclone intensity scale. After it was named, Hinano came under the influence of Cyclone Judy and started to move towards the northwest.
On March 29, TCWC Nadi started to monitor a westward moving tropical depression that had developed within a monsoon trough about x to the x of x. Over the next few days, the system moved towards the west before after it several large pressure drops were reported,
According to TCWC Nadi, a tropical depression existed between May 28 and May 30, to the far west of Fiji, with the associated cloudband located over Fiji between May 27 and May 31. The associated cloudband caused some flooding in low lying areas on the island of Viti Levu.
This table lists all the storms that developed in the South Pacific to the east of longitude 160°E during the 1989–90 season. It includes their intensity on the Australian Tropical cyclone intensity scale, duration, name, landfalls, deaths, and damages. All data is taken from the warning centers from the region unless otherwise noted.