The ENSO index shows a strong positive correlation with
the OND rainfall in all regions at the 1% significant level
(Table 2). Thus it is evident that El Niño conditions favor
rainfall for the entirety of Sri Lanka during (October,
November, December) (OND) season. During the 46
seasons in which the El Niño phase prevailed, 22 had
rainfall above the normal tercile (Table 3). In the normal
tercile, out of the 47 seasons El-Niño prevailed in 12
seasons while in 16, La Niña prevailed. Further during 46
seasons in which La Nina phase prevailed, in 24 seasons