Long-Term Climate Variability in Australia

Variation in Australian Climate

Long-Term Global Climate Variations

Long-Term Temperature Variations in Australia

Long-Term Rainfall Variations in Australia

Other Climate Variations in Australia

Long-Term Rainfall Variations in Australia

Paleoclimate records indicate that Australia's rainfall has been highly variable for many thousands of years. This is also supported by the fact that many native plants and animals have evolved to cope with extended periods of drought.
Australia's instrumental rainfall record is relatively short but does exhibit large year-to-year and decade-to-decade fluctuations. Some of the year-to-year rainfall variability can be accounted for by the El Niño - Southern Oscillation phenomenon.*

Because of the large year-to-year changes it is hard to detect any long-term trends in Australian rainfall. However, some weak trends in rainfall have been identified. The percentage area of Australia experiencing extreme wet conditions has increased slightly this century while the area of extreme dryness has reduced.

The number of heavy rainfall events has also increased over some areas of the continent. However, a decreasing trend in winter rainfall has been observed over southwestern Australia in the last 50 years. Not only is Australian rainfall highly variable with time, but its fluctuations also exhibit high spatial variability. This means that, whilst some regions might be unusually wet, at the same time, other parts of the country might be much drier than normal. This spatial variability is evident at both short and long time-scales. Maps of decadal mean rainfall also indicate that some decades are very wet whilst others are much drier than the long-term average. For example, the 1970s are noted for being a wet decade due to several very wet years during this time, whereas the 1930s were a relatively dry decade for much of Australia.

Decadal mean rainfall departures from the long-term mean