This thunder hour dataset is based on lightning observations from the Lightning Imaging Sensor (LIS) that operated aboard the International Space Station (ISS) from 1 March 2017 to 16 November 2023. The data are provided at 0.05° latitude/longitude resolution for latitudes between 54.75ºS and 54.75ºN. A thunder hour is defined as an hour during which thunder can be heard from a given location. Thunder hours represent a historical measure of lightning occurrence and a metric of thunderstorm frequency that is comparatively less sensitive to geographic variations in the detection capabilities of a lightning location system. Thunder hours represent the average number of hours per year during which two or more LIS group centroids were observed within 15 km of each grid point. The ISS LIS annual thunder hour dataset is available as a single netCDF-4 file.