Rain gauges record the precipitation that has fallen in a certain time interval. Since precipitation can vary greatly over small areas compared to other meteorological variables, its recording is almost mandatory for a local statement. Depending on the type of construction, precipitation is recorded cumulatively or (highly) resolved in time, whereby a recording of the water equivalent from snowfall can also be determined. Precipitation values are used for numerous purposes, for example, they are directly included in water balance analyses and are used in meteorology for weather forecasting. As long-term precipitation statistics, they can be used to determine cultivation plans for agriculture. For the recently more and more topical subject of flood analysis and forecasting, they serve as input values for model building.