Climatic condition is an important factor that may greatly affect the delineation of hybrid rice growing areas and its yield. Based on the data from nation-wide coordinated experiments, analyses are made of time and space variations of hybrid rice growth periods and the difference in the structural elements of yield for various rice growingareas. And climatic indices of structural elements of yield in different areas are computed in order to provide an agroclimatic basis for the delineation of hybrid rice growing areas.