Secondly, despite a latitudinal span of 13 degrees, average annual temperatures are remarkably uniform throughout the country. Owing to the increase in the height of the plateau towards the north-east, there is hardly any increase in temperature from south to north as might be expected. The third feature is the striking contrast between temperatures on the east and west coasts. Temperatures above 32 C are fairly common in summer, and frequently exceed 38 C in the lower Orange River valley and the Mpumalanga Lowveld. Frost, humidity and fog Frost often occurs on the interior plateau during cold, clear winter nights, with ice forming on still pools and in water-pipes.
Frost decreases to the north, while the coast is virtually frost-free.
Average annual relative humidity readings show that, in general, the air is driest over the western interior and over the plateau. Low stratus clouds and fog frequently occur over the cool west coast, particularly during summer. Sunshine South Africa is famous for its sunshine. Generally speaking, April and May are usually the most pleasant months. The hot summer weather has abated and the winds are lighter than during the rest of the year.