Building resilience to climate change and variability is essential for achieving sustainable development. In Cambodia, the economy depends on agriculture, mainly rice production. As most rice fields are rainfed and most farmers rely on their non-science-based experience, they are unwilling to adjust to changing rainfall. The aim is to provide information related to the changing water cycle, which could be used by local governments and farmers to adjust crops, planting time and water resources management accordingly. In this study, a hydrological model and rice growth model were coupled into a “Hydro-Crop” model and used to integrate satellite and in-situ data and general circulation model (GCM) outputs of CMIP3 to generate the desired information. In this manner, the hydrological conditions, optimum planting dates and yield for present and future climate were obtained and the results were compared with the actual situation.