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An important limitation of commonly used single site daily rainfall models is their inability to represent monthly characteristics of observed rainfall, whereas impact studies often demand the accommodation of such statistics of rainfall. In this study, a single-site model for simulations of daily and monthly rainfall in arid and semi-arid areas in the Middle East was developed. The rainfall generator is a Markov-Gamma model in which a first-order two-state Markov chain was used to determine the occurrence of rainfall and a two-parameter Gamma distribution was applied to simulate the rainfall amount on wet days. The basic structure of the generation process comprises the generation of a sequence of daily rainfall amounts and the adjustment of this daily rainfall by implementing the Thomas-Fiering monthly model. This procedure guarantees that important statistical characteristics of the daily and monthly rainfall are reproduced. Copyright (c) 2011 Royal Meteorological Society