The rainfall variability of each season over Thailand was exhibited by the EOF technique. The most dominant mode of each seasson the variability accounts for 47.5%, 24.1% , 31.0% , and 21.3% of the total variance respectively,had a spatial pattern with the same sign (positive) over almost all of Thailand.
The correlation analysis suggest that the Nino3,Nino3.4 SST index influence rainfall variability of each season over Thailand. Especially, the most correlation between the Niño3.4 with rainfall during March April and May.