South Africa has an average annual rainfall of 450mm, compared to a global average of 850mm. About 65% of the country receives less than this average, which is generally considered to be the minimum required for successful dry land farming. About 20% of the country, mainly the arid west, receives less than 200mm per year. In the Western Cape, the average rainfall is highest in the winter months, while in the other eight provinces the average rainfall is highest during summer. South Africa’s rainfall is unreliable and large variations in rainfall are the rule rather than the exception.