Scattered data interpolation refers to the problems of constructing a smooth surface through non-uniform and uniform set of data points. Besides that, this subject is very vital in various fields such as medical, sciences, engineering and others. There are many researchers who have done their studies in interpolation methods with different approaches and has been reported in many papers. There are two different approaches to the interpolation of scattered data where it can be clarified as global and local methods. The global method is influenced by all data while the local method is not influenced all the data where it effected at nearby points. This chapter discusses the rainfall distributions in several areas in Malaysia by using the rational quartic triangular patches.