The differences between temperatures in the animal occupied zone (AOZ) and temperatures measured by control system sensors are rarely explored. This experimental study quantifies the dry-bulb air temperature [hereinafter temperature] distribution inside a finisher pig building that combines natural ventilation through automatically controlled openings with a mechanical ventilation system. Year-long temperature data from 28 sensors located at 3 different heights in the building was analysed to help understand the temperature distributions and indicate the temperatures below or above an assumed optimal temperature range, defined as between 14 °C and 24 °C. Relatively large variations in the spatial temperature distribution were found, and they were higher in the vertical direction than in the longitudinal direction. The temperatures measured in the AOZ at 0.25 m height, were on average, 7 °C warmer than that at 1.5 m height. The AOZ temperature correlated better with temperatures measured at 0.7 m or 1.5 m height in the same pen than with temperatures measured in the AOZ at other pens. The analyses show that a proportional–integral based control system effectively counteracts the effects of outdoor wind conditions, and the control system is capable of maintaining the defined optimal temperature at the measurement height. However, the optimum temperatures at the measurement heights above AOZ do not correspond to the measured temperatures in the AOZ.