 The process of the surface urban heat island, Suhi, varies with latitude, climate, topography, and meteorological conditions. This study investigated the seasonal variability of Suhi in the Tehran metropolitan area, Iran. The study suggests that in semi-urban cities such as Tehran, with the urban rural indicator, a surface urban cool island may be observed in daytime while Suhi at night time. This article was authored by Cyrus Hashimi, Kehail One, Ali Darvishi, and others.