El Niño continued to strengthen during the monitoring period. The graph below (figure 5.x) illustrates the behavior of the Southern Oscillation Index (SOI) of the Australian Bureau of Meteorology (BOM) from October 2014 to October 2015. Sustained negative values of SOI below -7 indicate an EI Niño event, while sustained positive values above +7 are typical of La Niña. Values within therange (-7 to +7) indicate neutral conditions.

As shown in the figure, the SOI value stayed below 0 for most of the past 12 months, except in February 2015, after which it dropped continuously to reach a very negative value of -20.2 in October. Considering the consistently low negative value of SOI and tropical Pacific Ocean temperatures over El Niño thresholds, the status of the ENSO Tracker at the BOM is "real El Niño event as of October 2015"; it is likley that it will persist until the end of this year.

The strong El Niño has led to drier-than-normal conditions in A