In the construction for steel bridges, it is important to accurately evaluate the environmental characteristics of the local region. It is well-known that the salt accumulation affects the corrosion of steel bridges. In order to evaluate the corrosion durability for a bridge, the airborne salt level is investigated monthly for a year prior to construction of the bridge. It is acknowledged that the airborne salt level varies seasonally, and thus it is possible that the one-year monitoring result does not necessarily represent long-term annual conditions for the airborne salt level. These climate changes make it difficult for the engineer to evaluate the corrosion durability for the steel bridges over a period of 100 years. In this study, the authors invested efforts to develop a procedure of estimating the airborne salt level based on available meteorological information. The estimation results showed reasonable agreement with the measured airborne salt level. It is confirmed that the proposed concise evaluation procedure based on only wind direction and speed information is useful as a method for estimating the airborne salt level.