Description: The dataset consists of temperature measurements of the porous ground (loose volcanic breccia). The temperature data were acquired for 3 years, from 30 September 2009 to 14 September 2012. Name of the station BTL, site location Latitude: 37.780675° Longitude: 15.008787°. BTL station was located at a distance of about 120 m (meters) from the fumarole vents that developed at an altitude of about 2470 m a.s.l. (above sea level) on Mt. Etna's North-East Rift. Approximate location of the fumarole vents: 33S 500740E; 4181593N. The volcanic feature that suggested the label for the monitoring station (BTL) is the neighbor “Bottoniera Line of craters”, on the northern flank of Etna. The temperature data have been recorded on a vertical line of four PT1000 sensors (temperature range of –40 °C to 150 °C, accuracy ±0.2 °C, resolution ±0.1 °C); the distance between each sensor was 0.15 m, thus the total depth of the monitored profile was 0.60 meter. A data-logger (model EBRO EBI 2T-313 four-channel) protected by a watertight case, acquired and stored data every hour, for about three years. The stored data file was downloaded once, at the end of the monitoring period, and none touched the probes in the monitored site during the monitoring period of time. The uploaded file includes all the raw measurements for the temperature profiles showing a linear correlation (R2) higher than 0.990 because these have been used by the author for further evaluations of the heat flux from the ground, possibly related to the volcanic activity (Diliberto et al., 2018 (doi:10.1007/s00445-018-1198-0); Diliberto & Gennaro, 2022(doi:10.3390/app12094471)). The profiles of temperature showing a not ideal linear fitting (R2 lower than 0.990) have been filtered out from the dataset.