The GPM Ground Validation Autonomous Parsivel Unit (APU) HyMeX dataset was collected by the Autonomous Parsivel Unit (APU), which is an optical disdrometer that measures the size and fall velocity of single precipitation particles. The APU consists of the Parsivel (the precipitation measuring instrument), developed by OTT in Germany, and its support systems, which were designed and built by the University of Alabama in Huntsville. The HYdrological cycle in Mediterranean EXperiment (HyMeX) aimed to improve the understanding, quantification and modelling of the hydrological cycle in the Mediterranean, with emphasis on the predictability and evolution of extreme weather events, inter-annual to decadal variability of the Mediterranean coupled system, and associated trends in the context of global changeThe APU dataset for HyMeX provides precipitation data including raindrop size, raindrop counts, precipitation drop size, precipitation rate, precipitation amount, and snowflake size, snowflake counts, and snowflake distribution. The HyMeX APU data were collected in Italy and France from September to November 2012.