Above sea-level) it ffeezes so hard in December and January that skating is carried on on the sheet of water in the Buen Retiro; and, as winter throughout Spain, except in the maritime provinces of the north and north-west, is the season of greatest atmospheric precipitation, snowfalls are frequent, though the snow seldom lies long except at high elevations, The summers, on the other hand, are not only extremely warm but almost rainless, the sea-winds being deprived of their moisture on the edge of the plateau.
In this zone there prevails a genuine sub-tropical climate, with extremely warm and almost rainless summers and mild winters, the temperature hardly ever sinking below freezing-point.
Nevertheless, the west coast north of the Olifants river is practically rainless and there is great difference between day and night temperatures, this part of the coast sharing the characteristics of the interior plateau.
December, January, February and March are practically rainless; the rains, beginning in April or May, reach their maximum in July, August and September, and rapidly diminish in October and November.
This region is rainless, barren and inhospitable, absolutely destitute of vegetation except in some small river valleys where irrigation is possible, and on the slopes of some of the snow-covered peaks where the water from the melting snows nourishes a scanty and coarse vege tation before it disappears in the thirsty sands.