The 2004–05 South Pacific cyclone season was an above-average season in which tropical cyclones formed within the South Pacific Ocean to the east of 160°E. The season officially ran from November 1, 2004 to April 30, 2005, however a tropical cyclone could form at any time between July 1, 2004 and June 30, 2005 and would count towards the season total. The season got off to an early start, when Tropical Depression 01F developed near the Solomon Islands on October 28, three days before the official start of the season. The final disturbance of the season dissipated as the season was drawing to a close on May 1. The season was above-average in terms of activity, with 9 tropical cyclones and 5 severe tropical cyclones forming during the season. The season featured Cyclone Percy, the most intense of the season in terms of pressure.

The 2004–05 Australian region cyclone season was a slightly below average tropical cyclone season. It began on 1 November 2004 and ended on 30 April 2005. The regional tropical cyclone operational plan also defines a tropical cyclone year separately from a tropical cyclone season, which runs from 1 July 2004 to 30 June 2005.