The north-west and Namaqualand are classified as semi-desert due to the low annual rainfalls of less than 200 millimetres - in parts less than 100 mm. The cold Benguela current from Antarctica is responsible for this phenomenon, as air over cold water absorbs only small amounts of humidity, so that rain clouds rarely form. An occasional shower can be expected in the winter months, when big enough clouds build up over Botswana and northern Namibia that they extend down to this area. But normally it is dry and hot in the north-west of South Africa.
At the coast banks of morning sea-fog frequently develop, which dissolve around midday. In summer the temperatures right at the coast are very pleasant. As you move inland, it gets drastically warmer. It is particularly hot at the lower Orange River, where the temperature often exceeds 40 degrees Celsius (Upington is the hot-spot in SA). In winter the temperatures stay between 25 and 30 degrees during the day, and dip very much lower at night. Night frosts are not unusual. The nicest time of the year in this region is spring, when, after the short rainy season, innumerable species of wild flowers cover the country with a splendid coat of many colours.
The climatic conditions in South Africa are largely dependent on the altitude of the area in question and its proximity to one of the oceans. Climate does, therefore, vary considerably regionally. Click on a climate zone for details.