Morphological Optimization Strategies for Year-Round Outdoor Thermal Comfort in High-Density Coastal Commercial Built Environments: A Qingdao Case Study

High-density commercial areas in northern monsoon coastal cities face dual microclimate challenges: hot summers and harsh winters. This study aims to optimize year-round outdoor thermal comfort (Physiological Equivalent Temperature, PET) by exploring morphological optimization strategies in Qingdao. Combining field observations with ENVI-met simulations, we evaluated the impact of building density, street aspect ratio (H/W), and orientation. The results reveal a fundamental “seasonal mechanism conflict.” In summer, a 45% density point-tower configuration with a deep canyon profile (H/W ≈ 2.5) maximizes shade and sea-breeze ventilation. Conversely, in winter, a 35% density enclosed topology with an open profile (H/W ≈ 1.6) optimally blocks cold northwesterly monsoons and increases solar gain. To resolve these conflicting seasonal requirements, we propose a dynamic morphological equilibrium. We recommend adjusting the H/W ratio dynamically between 1.6 and 2.5 and adopting a southeast block orientation of 15–30° to synergistically guide summer breezes while blocking winter winds. Ultimately, this study shifts the design paradigm from static parameters to dynamic seasonal trade-offs, offering actionable morphological guidelines for climate-resilient built environments.