In the urban fabric of Athens, and more specifically at its centre, the high density and the geometry of the buildings can be the main reason for the diurnal temperature deviations that can be observed. The high global incident radiation as well as the storage capacity of the surrounding materials in a street and its surroundings, such as concrete, brick, concrete tiles and asphalt, converts the built environment to a radiator which releases its heat at night. Additionally, anthropogenic heat due to the intense use of private means of transportation as well as due to the use of mechanical cooling systems during summer, may exacerbate the problem. Moreover, the lack of vegetation and hence the lack of shading and evaporation usually leads to creation of unpleasant areas, especially for the inhabitants at the centre.