Level of annual rainfall

IBISWorld forecasts the level of annual rainfall to decrease by 8.2% in 2024-25, to 490.2 millimetres. At the time of writing only three months of rainfall data is available for the current year. As weather patterns are very difficult to predict, estimated rainfall levels in the current year are set to the long-term average.

Rainfall exhibits high volatility, with much of this coming from two global weather phenomena, La Niña and El Niño. El Niño is a weather phase that leads to above-average sea temperatures in the Pacific Ocean, creating warmer temperatures and reduced rainfall in Australia. La Niña is a weather phase that causes below-average sea temperatures in the Pacific Ocean, leading to wetter climate conditions in Australia. A La Niña weather phase often follows an El Niño weather phase. As of October 2024, the BOM's ENSO (El-Nino Southern-Oscillation) Outlook is set to La Niña Watch, indicating that a La Niña may develop later in 2024.

Prolonged drought conditions across much of the country saw rainfall fall over the three years through 2019-20. Rainfall in 2019-20 reached its lowest levels since 1951-52. Furthermore, the June 2019 to December 2019 was the driest on record for that time of year, likely contributing to the extensive 2019-20 bushfires. The BOM reported a La Niña event in September 2020, with a substantial shift toward cooler and wetter conditions occurring during the preceding months. These conditions contributed to above-average rainfall in 2020-21, with rainfall surging 48.1% over the previous year. Relatively high levels of annual rainfall persisted as La Niña weather events continued to influence the level of rainfall in Australia to near-record levels. November 2021 was the wettest November on record, while October 2022 was the second wettest on record. Overall, IBISWorld forecasts the level of annual rainfall to rise at a compound annual rate of 7.2% over the five years through 2024-25.