The ship campaign MSM114/2 (ARC) with the German research vessel Maria S. Merian took place from 22 January to 23 February, 2023. The campaign started in Mindelo, Cape Verde, and ended in Punta Arenas, Chile. During the campaign, the Intertropical Convergence Zone (ITCZ) was completely crossed three times at an almost constant longitude of 23˚W yielding three profiles of the ITCZ. Afterwards, a storm was passed in the Roaring Forties, in the South Atlantic. Here, we present level 1 radiosonde data as part of a series of standardised data sets of the atmospheric and oceanographic observations gathered during the ARC campaign. The radiosonde level 1 data set includes temperature, dew point temperature, relative humidity, mixing ratio, wind speed and direction as function of start time and flight time for each sounding.