The BACSAM II aircraft campaign, conducted with the polar research aircraft Polar 6 and the towed body T-Bird, took place from 3 April to 2 May 2024. It was based in Longyearbyen, Svalbard. In total, 11 low-level research flights and two transit flights were conducted, covering the region around Svalbard and north of Greenland. The KT19 was installed on the underside of Polar 6, facing the ground. The datasets present the KT19 observations, consisting of 50 Hz temperature measurements that correspond to surface temperatures during low-level, straight flight segments, together with the corresponding GPS positions.