Climate change is an important issue at the global now, and the changes of different weather factors such as temperature and rainfall have impacted to agricultural practices. Therefore, this study aims to assess the impacts of weather factors to rice yield in Vinh Chau town, Soc Trang province by analyzing the trends of observed (1984-2012) and simulated (2016-2044 from SEA START) rainfall and temperature; by simulating rice yield using Cropwat model in which the rice yield has been calibrated (2000 – 2005) and validated (2006 - 2012). The results show that rainfall has trend of decrease while the temperature has trend of increase (1984-2012). The future (simulated from SEA START, 2016-2044) rainfall will decrease significantly while temperature will increase. With the changes in rainfall and temperature, water demand for agriculture will increase in the future. In addition, the results from rice yield simulation under three scenarios show that the impacts of future rainfall and temperature to rice yield is very slightly in research area. Therefore, futher researches are needed to include the impacts of other factors in the simulation such as: rice variety, fertilizer and pestidide application in research area.