Severe Tropical Cyclone Ilona caused moderate damage across the Pilbara region of Western Australia in mid-December 1988.

Steady intensification occurred and Ilona reached its peak strength on 17 December as a low-end severe tropical cyclone.

On 12 December, a tropical low consolidated from the monsoon trough over the Timor Sea, west of Darwin, Northern Territory.

[2] Twelve hours later, the Joint Typhoon Warning Center (JTWC) also began issuing advisories, dubbing it Tropical Cyclone 03S.

[3] Decelerating somewhat, Ilona steadily intensified over the following days and achieved severe tropical cyclone status—having ten-minute sustained winds of at least 118 km/h (73 mph)—around 12:00 UTC on 15 December.

Slight intensification took place, with the cyclone achieving its peak strength around 00:00 UTC on 17 December with ten-minute sustained winds of 130 km/h (80 mph) and a barometric pressure of 960 hPa (mbar; 28.35 inHg).

[6] These winds uprooted trees, downed power lines, and tore roofs from homes in multiple locales;[2] extensive damage occurred in Roebourne, Wickham, Dampier, Karratha, Pannawonica, and Tom Price.

[7] Offshore, the combined effects of Cyclones Ilona and Orson in March 1989 caused tremendous damage to coral reefs—mainly populated by Acropora—in eastern areas of Mermaid Sound.