The pH of the soils is on the acid side although there are some areas with alkaline soils with pH as high as 8,0. The Cape flora thrives under highly variable climatic conditions. A maximum temperature of 32 o C is not uncommon during the summer months, particularly in the regions of the Sandveld and Cederberg. The mountain ranges are cooler, experiencing the effects of prevailing winds, mists and cloud. The minimum temperatures occasionally fall below 0 o C in many of these areas although not for long periods of time.
Snow falls regularly in the Cape mountains each winter.
Proteaceae occur in regions where the rainfall varies from as low as 180mm to 2500mm per annum, but many species occur in depressions, gullies, valleys and on south-facing slopes where the plants use underground moisture accumulated during the winter months. Protea cynaroides is a good example of this. It grows in areas with abundant underground seepage but with annual rainfall that varies from 300 mm to 1500 mm. A very important factor in the ecology of Proteaceae is a well-drained soil and efficient drainage system. This provides not only a well-aerated soil, but also a cool root system which is important.