Near-surface temperature and salinity data for Gradients 3 (April 9th – 29th, 2019) were acquired through the use of a thermosalinograph (THSL) system aboard the research vessel R/V Kilo Moana. Data were acquired every second and water samples were taken over the duration of the cruise for calibration of the THSL conductivity cell. Navigation data (latitude, longitude, and ships speed) were recorded throughout the cruise every ten seconds. The THSL data were interpolated at the navigation data times.