Sri Lanka, being a tropical island, is characterized by rainfall into three main climatic zones in which have striking seasonality and great inter annual variability. As many researchers have revealed, the Wet zone receives enough rainfall while the rest of the Intermediate zone and the Dry zone receive lesser rainfall, which leads to deficiency of water. It is very important to say that the Intermediate and the Dry zone cover more than 75% of the total land extent of Sri Lanka and stand as the main agricultural land in the country. Hence, historically and traditionally, irrigated agriculture has been very popular with the seasonality of rainfall. As an agricultural society prevails in these zones, people concerned much on rainfall than any other climate element in the past and in the present as well and people have treated rain as a God. In that sense, identifying temporal variability of rainfall in the Intermediate zone and the Dry zone is much important to decision and policy makers to perform well planned activities and to ensure a sophisticated life for people.