This study, the correlation between Niño SST index (blue) and principal component time series of seasonal (red) shows in Figure 4 for each of the season represented by PC1 of data of Thai Meteorological Department and the correlation coefficient between them is shown in Table1. The value is positive for all seasons, because a high SST anomaly gives a high rainfall anomaly, and a low SST anomaly gives a low rainfall anomaly. 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.