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In this study the data collected by 16 automatic rainfall stations distributed uniformly across Peninsular Malaysia are analysed using a Rainfall Event Mining Tool (RainEMT) developed by the authors in Microsoft Access, using Visual Basic for Applications. RainEMT allows the easy extraction of large‐scale rainfall event data such as the total number of yearly or monthly rainfall events, annual maximum rainfall or annual maxima series, and event total rainfall, with threshold selection from a large time series rainfall dataset. The rainfall events are separated by a user‐defined minimum inter‐event time (MIT).

RainIDF, a software tool for derivation of rainfall intensity-duration-frequency (IDF) relationship is developed as an Excel add-in by using Visual Basics for Applications (VBA). The tool is integrated with two of the most widely used statistical distributions for determination of IDF relationship: the generalized extreme value (GEV) distribution for annual maxima series, and the generalized Pareto (GPA) distribution for partial duration series (PDS). It provides automated distribution fitting for rainfall data in the form of annual maxima or PDS for multiple intervals, solving and plotting of rainfall IDF curves. RainIDF uses the Solver add-in function in Excel to solve the coefficients of the empirical IDF formula in one step. The methodology built into RainIDF is discussed and rainfall IDF relationships for several stations in Peninsular Malaysia are derived and compared. RainIDF is available for download on GitHub

The minimum inter‐event time (MIT) between two wet periods has to be set in order to separate rainfall events. The objective of this study is to analyse the effect of MIT on rainfall events in Peninsular Malaysia. Rainfall event data from 16 rainfall stations, containing the annual number of rainfall events together with the number of events that exceed a certain range of duration values, have been extracted using RainEMT. It is found that the average total number of rainfall events will be higher with smaller MIT values.

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