The 2017–18 Australian region cyclone season was an average period of tropical cyclone formation in the Southern Indian Ocean and South Pacific Ocean, between 90°E and 160°E, with 11 named storms, which 3 intensified into severe tropical cyclones. Another two tropical cyclones, Cempaka and Flamboyan occurred outside the Australian region but are included in the descriptions below. The season officially began 1 November 2017 and ended on 30 April 2018; however, tropical cyclones can form at any time of the year, as demonstrated by the first tropical low of the season in early August. Any tropical system that forms between 1 July 2017 and 30 June 2018 will count towards the season total. During the season, tropical cyclones will be officially monitored by one of the five tropical cyclone warning centres (TCWCs) that operate in this region. Three of the five centres are operated by the Australian Bureau of Meteorology (BOM) in Perth, Darwin and Brisbane, while the other two are operated by the National Weather Service of Papua New Guinea in Port Moresby and the Indonesian Agency for Meteorology, Climatology and Geophysics in Jakarta. The Joint Typhoon Warning Center (JTWC) of the United States and other national meteorological services, including Météo-France at Réunion, also monitored the basin during the season.

Perth is the capital city of Western Australia. It is the fourth most populous city in Australia, with a population of over 2.3 million within Greater Perth. It is part of the South West Land Division of Western Australia, with the majority of Perth's metropolitan area on the Swan Coastal Plain between the Indian Ocean and the Darling Scarp. The city has expanded outward from the original British settlements on the Swan River, upon which its central business district and port of Fremantle are situated.