Accurate and reliable precipitation measurements play a key role in a wide range of applications like flash-flood forecasting, water resources management, and climate change projections and mitigation policies. However, in-situ measurements of liquid precipitation have experienced little conceptual innovation for many decades now. Rain gauges were the first devices adopted to measure the rainfall accumulated at given location in each time interval. Although prone to instrumental and environmental biases, rain gauge measurements are the most trusted forcing variables of hydrological models. Precipitation measurement biases of traditional catching type gauges were investigated in a past PRIN 2015 project through both numerical simulation and wind tunnel tests, which showed that their assessment and correction require detailed knowledge of the rainfall microphysical characteristics, typically expressed through the size distribution of raindrops (DSD) and the corresponding actual fall velocities.