Cyclones bringing rain to Queensland during the years 1925-1936 are classified as coastal, northern, or inland and their influence on monthly rainfall investigated. It is found that with coastal cyclones heavy falls were limited to comparatively small areas so that the cyclones did not cause excess rain at many stations, but they often ensured average rain at the coast when the greater part of the State had poor falls.
Northern cyclones were confined to the first three months of the year; those from the east caused heavy falls on the north coast, rain, decreasing sharply in adjacent divisions. Stationary cyclones and those from the Northern Territory which brought good rain to the country south of the Gulf of Carpentaria, in most cases affected the monthly totals at only one or two stations.
Inland cyclones which were not very intense, the isobars being widely spaced, generally caused widespread rain. Excess rain was experienced at several stations during most months that these cyclones occurred, a large part of the good rain being due to the cyclones.
A comparison of the excess rain brought to the various stations by cyclones with that due to other causes shows that cyclones were responsible for approximately one-third of the good rain that fell in Queensland during the first three months of the year, for much less between April and July, and for very little in the remainder of the year.