Abstract:
Rainfall in Pekanbaru has a high intensity compared to other cities in Riau Province but
during 2010-2020 the intensity becomes uncertain so it is important to forecast rainfall so that
planning in all areas of human life such as agriculture, development, and so on can be
maximized. Rainfall forecasting using the ARIMA model is considered less significant, so it
developed into an ARIMAX model with the transfer function model method, involving
exogenous variables which are assumed to affect endogenous variables. This study aims to
predict the rainfall in Pekanbaru using a transfer function model with a disturbance series
with wind speed as the exogenous variable. The data is divided into two, namely in sample
data (rainfall data and wind speed for the January-December 2020) and out sample data
(rainfall and wind speed data for the January-December 2021). Based on the results of the
study, it was found that the rainfall forecasting for Pekanbaru from January to December
2021 was known that the rainfall that occurred ranged from -128 mm to 561 mm in the lowhigh
rainfall category with a MAPE of 14% which is a good result.
