chapter  19
The Sudan
Pages 30

From a point a little north of the town of Port Sudan, one can draw an isopleth westwards, keeping to the north of Atbara and Khartoum, and reaching the western frontier of the Sudan at approximately i f N latitude. This line would then delimit a northern zone of indeterminate or slight winter maximum of rainfall from much of the rest of the Sudan, which has a summer rainfall maximum - thus defining in one sense the southern frontier of our ‘ Middle East ’ . But there is a zone of aridity even within the region of summer maximum (the 250 mm isohyet occurs south of Khartoum), and this zone of low rainfall (even though now with a summer maximum) reinforces for much of the central Sudan the concept of a hot, arid environment which we take as being ‘ Middle Eastern’.