In the Rain Sense kickstart project of the Amsterdam Institute for Advanced Metropolitan Solutions (AMS), sensors and citizens are preparing Amsterdam for future weather. Urban areas often lack rainfall information. Hence, new rainfall measurement techniques are important. E.g., the number of observations may be increased by employing microwave links from operational cellular telecommunication networks. Rain-induced attenuation and, subsequently, path-averaged rainfall intensity can be retrieved from the signal's attenuation between transmitter and receiver of a link (Figure 1). Although this new potential source of rainfall information is promising (e.g. Messer et al. (2006), Leijnse et al. (2007), Overeem et al. (2013)), its quality needs to be demonstrated more extensively, which is done here for Amsterdam.