We present the OpenRainER dataset of precipitation measurements, available open-source on Zenodo repository at <a href="https://doi.org/10.5281/zenodo.10593848" target="_blank" rel="noopener">https://doi.org/10.5281/zenodo.10593848</a>. The dataset contains mainly precipitation related measurements over the region of Emilia-Romagna in northern Italy. Inside OpenRainER, measurement from the commercial microwave link network managed by Lepida S.c.p.A. are published, consisting in 1 min time series of the transmitted signal level and of the received signal level over 151 radio links. These data are primarily generated for link quality monitoring; however, they can be opportunistically exploited for weather monitoring as there is a well known direct relationship between rainfall intensity and decrease of the received signal level. The data are stored in NetCDF format and can be processed and converted into rainfall intensity time series along each radio link path using open-source tools developed within the COST Action OpenSense framework. We also provide concurrent data from the regional operational rain gauge network and two weather radars, as a reference for calibration and validation purposes. OpenRainER has peculiar characteristics with respect to similar open datasets: (1.) The links are distributed over very different types of terrain, including plains, hills, valleys, and mountain ridges (up to 2000 m a.s.l., and both densely inhabited cities and rural areas. (2.) While conventional CML networks show a frequency distribution inversely proportional to the link path length, here links operate at 24.6 or 25.6 GHz. This offers a wider range of sensitivities for testing classification and retrieval algorithms.