The published data set consists of measurements performed by the active cloud radar as part of the Microwave Radar and radiometer for Arctic Clouds (MiRAC; Mech et al., 2019) operated on board the Polar 5 research aircraft during 19 flights of the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, carried out in early summer 2017 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of radar reflectivities of the FMCW 94 GHz cloud radar transformed to nadir view as well as brightness temperature measurements at 89 GHz with a 25 deg backward inclination with respect to the aircraft's fuselage. The data set has been quality-checked and is available in NetCDF format for each flight separately.