As streets cover almost twenty-five percentages of the urban open spaces, designing streets is a vital issue in creating thermal comfort for urban environmental design. The geometry of the street (height/width ratio) as well as orientation directly influences the airspeed, solar access in urban canyon and as a result thermal comfort at the pedestrian level. This study examined the street geometry case study's scenarios with different street geometries and investigates its effects on outdoor thermal comfort as well as the weather parameters. However, according to the matrix assessment conducted by the author, the vast street canyons (height/width=0.65 m/14.5 m with an orientation parallel to the prevailing wind direction achieved the best results. Nevertheless, the aim of this paper is to investigate the impact of street canyon geometry on outdoor thermal comfort and its parameters in the summertime using numerical modeling.