This paper describes a climatic analysis of landscape strategies for outdoor cooling in a hot arid region, accounting for the efficiency of water use. Six landscape strategies were studied, using different combinations of trees, lawn, and an overhead shade-mesh. The effects of these treatments were tested in two adjacent courtyards at Sde-Boqer, in the Negev Highlands of southern Israel, during summer (July-August). On average, air temperature in the non-vegetated exposed courtyard reached a maximum of about 34°C in mid-afternoon. Compared to this base case, a configuration with shade trees and grass yielded a daytime temperature depression of up to 2.5°C, while shading the courtyard with a fabric shading mesh, counter-intuitively, caused a relative increase of nearly 1°C. Unshaded grass was found to provide only a small air temperature depression and had the highest water requirement. However when the grass was shaded, either by the trees or by the shade mesh, a synergic effect produced greater cooling as well as a reduction in total water use of over 50%. The "cooling efficiency" of these strategies was calculated as the ratio between the sensible heat removed from the space and the latent heat equivalent of the evaporated water. This measure is proposed as a criterion for evaluating landscape strategies in arid regions, where the water resource is scarce.