The variations of meteorological conditions significantly influence human comfort. People often experience greater discomfort when the weather is both hot and humid. Such a discomfort feeling does depend, in part, on the ability of human body to lose heat via evaporative cooling. Since a considerable portion of Iranian population are living alongside the coastal regions in southern and northern parts of the country, combined increase of temperature and humidity could cause physical discomfort for these people. In recent decades, researchers have introduced heat index or apparent temperature index that gauge the impact of combined temperature and humidity on human comfort. In the present study the amounts of apparent temperature for two Iranian cities (Yazd and Gorgan) are computed and compared. Gorgan is situated near the western side of the Caspian Sea coasts. In contrast, Yazd is located in central parts of the country, far from sea and moisture-laden winds. Suitable calculation methods are selected to measure the amounts of apparent temperature for critical hot and muggy conditions. It was concluded that during hot summers, the potential of sunstroke, heat cramps or heat exhaustion, in Gorgan is greater than these hazards for Yazd.
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