Despite the relatively short history, the TRMM rainfall products have been widely used in many areas, such as, monitor the recent severe drought in Afghanistan; estimate maize yield potential in SE Asia. To detect climate changes/anomalies, it is necessary to have climate data for comparisons. Willmott et al. applied various techniques to estimate global climate data based on surface observations between 1950 - 1999. Because the observational methods of the surface and satellite products are very different, comparisons are needed to understand existing biases. We are developing a system that will allow users select different rainfall products, an area of interest and a time period and generate graphic (scatter, line, area) output. Application examples will be given.