Indian summer monsoon rainfall (ISMR) has three important attributes for its proper representation – viz total seasonal quantum, its spatial and temporal distribution over the different Indian land mass for the four monsoonal months. Traditionally only the all India area – weighted average rainfall of the season as a whole, has been used as a single index to study the interannual variations and teleconnections with other global parameters.

In this study, using 115 years of ISMR gridded data, we have proposed two new indices - the Temporal and the Spatial Indices, besides the Quantum Index (in vogue). These indices for any year depend on the number of Normal rainfall Days and number of Normal rainfall Grids during the year. It is suggested that the incorporating all three indices will be a better way to study the Indian monsoon intra seasonal – inter annual variabilities. Case studies of a few good and poor monsoon years are discussed to highlight the importance of the new indices.