Indonesia is a country with a tropical climate so the region has a fairly high rainfall. Pekanbaru City generally has a tropical climate with maximum air temperatures ranging from 34.1º C - 35.6º C and minimum temperatures between 20.2º C - 23.0º C. In this study, predictions of the rainfall period of Pekanbaru City were made from 2016-2020. This study used the Fast Fourier Transform m…