Trend analysis is one of the most commonly used tools for detecting changes in climatic and hydrologic time series. Attempts are devoted to the study of seasonal climatology in Syria, including information on the level of rainfall at various climatic stations in Syria for the period 1991-2009. Wet (from October to May) and dry (June to September) seasonal precipitation are obtained from surface observations. There are numbers of statistical tests that exist to assess the significance of trends in time series. However, the existence of positive autocorrelation in the data increases the probability of detecting trends when actually none exist, and vice versa. Most of the recent studies about climate change suggest that the behavior of some of the climatological variables has already changed and will continue to change towards increasing or decreasing magnitudes and frequencies, depending on the type of variable. Increased rainfall and following floods are expected in some regions while other regions will experience smaller rainfall and longer droughts, meaning water scarcity.