Human thermal comfort is defined as a condition of mind, which expresses satisfaction with the surrounding environment. High temperatures and humidity provide discomfort sensations and sometimes heat stress (i.e., reducing the body’s ability to cool itself). Moreover, discomfort and heat stress reduce productivity of workers and may lead to more serious health problems, especially for aged persons. In hot summer seasons of arid regions, high outdoor air temperatures due to intensive solar radiation and low relative humidity are present. Consequently, discomfort sensations and heat stress are expected. Therefore, persons should take care when they go outside in hot summer to protect their health from heat and/or sunstroke.