Dataset contains INP concentration data measured at Sammaltunturi, Lapland, Finland in 2023. The INP concentration is determined via the Ice Nucleation Spectrometer of the Karlsruhe Institute of Technology (INSEKT) and normalized to the volume of air sampled. Uncertainties represent the 95 % confidence interval and data is provided on a event-based grid, i.e. a new data point is given for each freezing event.