Next past The result of the relationship between the Nino 3,Nino 3.4 SST index and the standardized PC of March, April and May (MAM) at various lag times.. shown in this table. The highest correlation of 0.49385 and 0.55586 indicates that the Niño3 and Niño 3.4 SST index leads the standardized PC values by 1 month.