Figure 3: Origins of tropical cyclones by season (early season - March to mid-July, mid-season - mid-July to mid-October, and late season - mid-October to January) for the five years during the period 1970-91 with the five highest values of the March-January average of the Southern Oscillation Index (SOI) or Las Niñas [panel (a)] and for the five years with the lowest values of the March-January average of the SOI or Los Niños [panel (b)], (from Lander 1994).