Urban street canyons significantly influence local climate conditions by regulating solar radiation and thermal energy exchange. This chapter explores the geometric characteristics of urban street canyons and their role in modifying solar radiation exposure at the street level. Key view factors, including the sky view factor (SVF), tree view factor (TVF), and building view factor (BVF), serve as primary indicators of urban morphology and are critical for understanding urban thermal environments. This chapter reviews different methods for quantifying these view factors, including 3D model simulations, fisheye photographic analysis, and street-level sensing through panoramic images such as Google Street View. Additionally, this chapter delves into the physical basis of solar radiation at the street level, discussing direct, diffuse, and reflected radiation within high-density urban environments. The integration of these view factors into solar radiation estimation provides insights into the impact of urban geometry on microclimate conditions, urban heat island effects, and outdoor thermal comfort. The findings contribute to urban planning strategies aimed at improving climate resilience and human well-being in dense metropolitan areas.