This study, the relationship between Niño SST index and principal component time series of seasonal for each of the season represented by PC1 of data of Thai Meteorological Department and the correlation coefficient between them is shown in Table. The value is positive for all seasons, With most positive relationships between MAM season with Niño 3.4 is 0.63188. Values estimated to be significant at 95% are bolded by Student’s t-test.