In this paper, the isopleth chart technique is used to develop comfort
zone charts. The usefulness of the isopleth technique is demonstrated
by applying it to Riyadh's and Jeddah's data. Comfort temperature ran
ges have been prepared and comfort zone charts have been developed for
both cities by applying these ranges to the dry bulb temperature isop
leths. Also, the microclimatic characteristics of both cities have bee
n identified by analyzing the dry bulb temperature, wet bulb temperatu
re, relative humidity of air, wind speed and direction, and solar radi
ation. The analysis shows that the climate of Riyadh can be identified
as hot-dry with a desert sub-zone and the climate of Jeddah as hot-dr
y with a maritime desert sub-zone. Based on these microclimatic charac
teristics, recommendations are presented for the design of buildings i
n the Riyadh and Jeddah area which may also be useful in similar clima
tes elsewhere.