Outdoor seating in urban underpasses plays a subtle yet significant role in shaping their microclimate. These seating arrangements can influence airflow patterns, temperature regulation, and humidity levels within these often-enclosed spaces. When strategically placed, benches or other seating can disrupt stagnant air, promoting better ventilation and reducing heat buildup. However, poorly designed seating may obstruct natural airflow, exacerbating stuffiness or creating wind tunnels. Materials used for seating also matter—metal absorbs and radiates heat, while wood or composite materials may have a milder thermal impact. The presence of seating can alter pedestrian movement, indirectly affecting how people experience the underpass's microclimate. Urban planners must balance functionality with microclimate considerations to create comfortable, inviting spaces beneath our cities.