The response of active-layer thickness and the ground thermal regime to climatic conditions on the Ulu Peninsula (James Ross Island, northeastern Antarctic Peninsula) in 2011–13 is presented. The mean air temperature over this period was –8.0°C and ground temperature at 5 cm depth varied from –6.4°C (2011–12) to –6.7°C (2012–13). The active-layer thickness ranged between 58 cm (January 2012) and 52 cm (February 2013). Correlation analyses indicate that air temperature affects ground temperature more significantly on snow-free days (R2 = 0.82) than on snow cover days (R2 = 0.53). Although the effect of snow cover on the daily amplitude of ground temperature was observable to 20 cm depth, the overall influence of snow depth on ground temperature was negligible (freezing n-factor of 0.95–0.97). Copyright © 2015 John Wiley & Sons, Ltd.