The instability of wind in speed and direction could lead to vibration in the structure and cause its damage. Because the meteorological data to be take in the longer period but free-vibration period of the construction is order of magnitude in second, the present data to describe instability of wind does not meet the demand of the construction motive analyzing. The observation of simultaneous change of wind speed and direction by seconds at seaside, mountain and outskirts of a city shows that instability of wind is less in the seaside and is more in the outskirts and wind observed is some instability in different direction of wind in the mountain site. It indicates the unsteadiness of natural wind in the wind velocity and direction is mainly related with the landforms and relief. Therefore, the wind dynamical analysis is necessary for constructions working in the disadvantageous landform conditions.