The result analysis of the eigenvectors and principal component time series (PC's) of DJF in the first mode show that the relation or the variance of the eigenvectors is positive over the central, western the eastern part of southern and some area of northern region of Thailand but it is negative over the northeastern, northern and eastern part western of southern of Thailand, as shown in figure 3.5 1(a). Figure 3.5.1(b) shows the values of standardized (PC’s), which have positive and negative values. It was found that there was the most positive in 1967 found over the central, western the eastern part of southern of Thailand there was high rainfall. On the contrary there was the most negative in 1990 found over the central, western the eastern part of southern of Thailand there was low rainfall and vice versa.