Figure 11: Correlations between number of Australian tropical cyclones observed in the total cyclone season and three-month averages of three variables associated with ENSO. The thick horizontal bar indicates the extent of the cyclone season. Central month of three-month averages of the ENSO variables are indicated on the horizontal axis. Data are from 1964-1982. All correlations are calculated on at least 18 pairs of observations (from Nicholls 1984).