This post is just to mention our recent papers devoted to describing a new drought index, the Standardised Precipitation-Evapotranspiration Index (SPEI). In the SPEI web site we discuss the motivation for a new index, describe the calculation process and give some examples. A software, SPEIcalc, has been created to automatically calculate the SPEI over a wide range of time scales. The software is freely available from Digital.CSIC, the institutional repository of the Spanish National Research Council (CSIC). The SPEI has been used to develop a Global 0.5º gridded SPEI dataset for the period 1901-2006, which is available for download.