•Long-term monitoring data of wind and bridge response were presented from the Hardanger Bridge.•The bridge response exhibited variable results.•The relationship between wind field and bridge response was studied using response surface methodology.•Variability in response is attributed to the variable wind field.•The variability in the wind field should be considered in design. Long-term monitoring data of wind velocities and accelerations on the Hardanger Bridge are used to investigate the relationship between the wind-loading and response processes. The extensive measurement system consisting of 20 accelerometers and 9 anemometers is described as well as the local topography of the site. The wind and response characteristics are presented using scatter plots and wind rose diagrams. The considerable variability observed in the bridge dynamic response is investigated by utilizing response surface methodology. Simple parameters of the wind field are selected as the predictor variables in the analyses. The variability in response is attributed to the variable wind field, and the effects of the significant parameters on the response are presented in a statistical framework. The agreement of the findings with previous considerations and the implications on the design of long-span suspension bridges are discussed.