This rainfall is mainly cyclonic and orographic but very occasionally thunderstorms do occur. The mountains to the east of the CMA are sometimes snowcapped but the snow layer never persists throughout the winter. Common cloud formations over the CMA are low-lying dark grey nimbostratus clouds and orographic clouds that often cover mountain tops. The average daily maximum temperature of the CMA is about 28 C in mid-summer and 17 C in mid winter. Figure 2 shows the mean annual temperature for the period 1992 to 1998.
Temperature can therefore vary depending on micro-climatic conditions that exist.
In the summer, winds are almost exclusively southerly and result in the formation of orographic cloud on Table Mountain. In winter north-westerly winds are frequent and often spell rainy weather. Winds over the CMA can reach gale force. Climate change is caused by anthropogenic factors such as industrial activity, transportation of goods and people and the burning of fossil fuels. These activities result in the production of greenhouse gases including carbon dioxide.