The dimensional relationships of Urban Canyons (CVU) of the City of San Juan-Argentina (31°32′ South latitude, 68°30′ West longitude), are studied in terms of the incidence of global solar radiation in winter and summer, analyzing the sky vision angles. Measurements of global solar radiation, temperature and humidity for winter and summer, as well as reports of the constituent urban elements were carried out by studying a sample of Urban Canyons of the city. Through the analysis of the radiation conditions along the East-West and North-South directions of the urban layout, the Free Angles of Building Mask and the Net Sky Vision Angles are obtained. These angles consider the obstruction produced by the construction and the urban grove to the solar radiation. Once the graphs of both climatic seasons are correlated, the optimum vision angles to the sky are defined. Consequently the CVUs presenting the most suitable proportions regarding the solar radiation are obtained as a contribution to the bioclimatic urban potential.