The outdoor wind and air flow around buildings affect the indoors in several ways. Wind is the primary driver for natural ventilation by exerting pressures (both positive pressure and negative suction) on building surfaces. Wind also can cause building exhausts to migrate outdoors to nearby air intakes and pedestrian locations, creating poor air quality indoors. This presentation focuses on approach wind conditions, the air flow patterns around buildings and wind pressures exerted on buildings. These effects are the fundamental starting place for more detailed ventilation and air quality analyses. Also discussed are modeling methods using CFD and wind tunnel similarity.