Records of Australian climatic statistics, obtained from the Australian Bureau of Meteorology, have been analysed to investigate the relationship between cloud cover, precipitation, temperature and the Southern Oscillation Index (SOI). In particular, the role of cloud cover in climatic change is considered. Analyses show a close correlation between precipitation and cloud cover and an inverse correlation between the diurnal temperature range and cloud cover. Significant long-term trends are evident in the data, with an increase in cloud cover and a decrease in the diurnal temperature range. There is also a slight increase in daily mean temperature, but no significant long-term change in precipitation (although the lack of significant trend may, in part, be due to the shorter length of record). The fluctuations in cloud cover, diurnal temperature range and precipitation are correlated with the SOI. Correlations of cloud cover with SOI are strongest for the northeast and weakest for the southwest of the continent.
P.A. Jones (Sun,) studied this question.