Next composite analysis, NOAA uses SST index for identifying El Niño (warm) and La Niña (cool) events in the tropical Pacific. It is the seasonal mean SST anomaly for the Niño3 and the Niño3.4 region. Strong events are defined above the ≥1.5°C (greater than or equal to 1.5 C) anomaly for warm events and at or below the ≤-1.5°C (less than or equal to -1.5 C) anomaly for cold events . Strong ENSO events are listed in Table.