Thermal infrared imagery (TIR) is a useful tool to detect and quantify the surface temperature anomalies associated with geothermal fields. Accurate detection of anomalies in surface temperature is an important aspect of geothermal research. Although day-time TIR images have long been used for temperature anomaly mapping, the increase in the spatial resolution and the number of acquisitions of nighttime thermal imagery provide new perspectives to the remote geothermal monitoring and exploration. However, the nighttime thermal imagery requires appropriate corrections in order to minimize some major artefacts. These corrections are namely: the masking of small scale thermal anomalies by the lapse rate, the relict diurnal heat due to the radiation of sun and the slope effect. Moreover, the correction of nighttime TIR imagery according to the altitude, slope aspect and the slope of the study area provide more reliable data.