We report 3 years of data from one meteorological and three smaller stations in University Valley, a high-elevation (1677 m) site in the Dry Valleys of Antarctica with extensive dry permafrost. Mean air temperature was -23.4°C. Summer air temperatures were virtually always < 0°C and were consistent with the altitude lapse rate and empirical relationships between summer temperature, distance from the coast and elevation. The measured frost point (-22.5°C) at the 42 cm deep ice table is equal to the surface frost point and above the atmospheric frost point (-29.6°C), providing direct evidence that surface conditions control ground ice depth. Observed peak surface soil temperatures reach 6°C for ice-cemented ground > 15 cm deep but stay < 0°C when it is shallower. We develop an energy balance model tuned to this rocky and dry environment. We find that differences in peak soil surface temperatures are primarily due to the higher thermal diffusivity of ice-cemented ground compared to dry soil. Sensitivity studies show that expected natural variability is insufficient for melt to form and significant excursions from current conditions are required. The site's ice table meets the criteria for a Special Region on Mars, with 30% of the year > -18°C and water activity > 0.6.

Dry permafrost - ground with temperature always below 0°C and containing negligible ice - overlying ice-cemented ground has been reported in the Dry Valleys of Antarctica and on Mars. Here we report on a new site (79°49.213'S, 83°18.860'W, 718 m elevation) located on the side of Mount Dolence in Ellsworth Land, Antarctica. Year-round temperature and humidity measurements indicate that dry permafrost is present between depths of 13.5 and 49.0 cm - the location of ice-cemented ground. The mean annual frost point of the ice-cemented ground is -17.0 ± 0.2°C and the mean annual frost point of the atmosphere is -22.7 ± 1°C. The corresponding mean annual temperatures are -19.2°C and -20.3°C. Neither the temperature of the ice-cemented ground nor the air rise above freezing. Both the dry permafrost and the ice table may be habitable. In the dry soil at 3 cm depth there are 80 hours in the summer when temperature exceeds -5°C and water activity exceeds 0.8. At the ice table, temperature exceeds -10°C and water activity exceeds 0.8 for 35 hours in the year. The ice table and the dry permafrost above it would be considered a ‘Special Region’ on Mars. Further microbial investigation of this site is indicated.