Vertical profiles of air temperature, humidity, pressure, and the horizontal wind vector measured by dropsondes (type RD41) released from Polar 5 during MOSAiC-ACA in August/September 2020. The profiles cover altitudes between the flight level of Polar 5 (typically about 3 km) and the surface. Observations during MOSAiC-ACA cover a range of cloud-free and cloud covered situations over open ocean and the marginal sea ice zone around Svalbard. The ASPEN software package (Martin, C; Suhr, I, 2021) was used to correct the raw data for the slow time response of the temperature sensor and to remove the known humidity bias. Data close to the aircraft, where the sensors still did not adjust to the outside temperature, and invalid measurements were removed by the quality check of ASPEN. To resolve temperature and humidity changes at cloud top the time response of the sensors has been corrected by an alternative method following Miloshevich et al. (2004). Additionally, the relative humidity has been corrected for the ageing of the sensor as described by George et al. (2021) to reach the saturation level of 100% inside clouds. The correction factor was determined individually for all dropsondes and was about 1.025 for the majority of sondes.