South Africa is a water scarce country. Key to building resilient settlements, guiding investment and design response is characterising aridity. The Aridity map is now available online on the StepSA website for free use as part of a series of climate indicator maps.


The De Martonne (1926) method was used for determining aridity index values for South Africa. Based on these values, the climate was zoned into six regions namely; arid, semi-arid, dry sub-h mid, moist sub-humid, humid and very humid.

For an interactive view of the indicator click here


Alternatives to Martonne’s aridity index are Thornthwait’s precipitation effectiveness index and UNESCO aridity index model.

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