There are few countries in the world where they have special characteristics including weather conditions, wind direction, and topography. In other words, some countries have multi-climate regions, and needed to be investigated more precisely. Based on these conditions, several cooling systems can be used for each region. In this study, the potential of the direct evaporative cooling (DEC) systems, indirect evaporative cooling (IEC) systems, desiccant wheel (DW) with DEC systems, and combination of theses methods for cooling in the cities of Iran are investigated. In the remaining regions, mechanical cooling systems and absorption systems can be used. According to weather condition and natural resources for water in Iran, DEC can be considered as a serious alternative for cooling. In this paper, based on numerical simulation and long-term meteorological measurements, general set of criteria is obtained. Results show that according to population dispersal DEC systems can provide comfort conditions for 53% of people of Iran. IEC, DW, combination of these systems, and mechanical cooling systems can supply comfort condition in remaining major cities of Iran consequently. Moreover, for showing the uniqueness of weather condition which leads to these varieties of climates, other important cities in the neighboring countries are compared with this numerical simulation code. (C) 2008 Elsevier B.V. All rights reserved.