The high Drakensberg mountains, which form the south-eastern escarpment of the Highveld, offer limited skiing opportunities in winter. The coldest place on mainland South Africa is Sutherland in the western Roggeveld Mountains, where midwinter temperatures can reach as low as −15 °C (5 °F). The Prince Edward Islands have colder average annual temperatures, but Sutherland has colder extremes. The deep interior of mainland South Africa has the hottest temperatures: a temperature of 51.7 °C (125.06 °F) was recorded in 1948 in the Northern Cape Kalahari near Upington,[68] but this temperature is unofficial and was not recorded with standard equipment, the official highest temperature is 48.8 °C (119.84 °F) at Vioolsdrif in January 1993