ESDU 93013 provides data for the rate of change with wind direction of the force components in the directions of the principal axes of the structure. The values are an essential input to the calculation methods of ESDU 89049 and 91010 for calculating the response of structures to buffeting by across-wind turbulence and the response in galloping, respectively. For building shapes, essentially prismatic blocks with only small edge rounding, tables give values for the two components for a range of cross-section aspect ratios and three levels of along-wind turbulence intensity; the values were obtained from the force correlations in ESDU 80003. For beam sections, values for both components are given for angle, channel, I-, H-, T- and X-sections and for two channel sections back-to-back; the data were obtained from the correlations in ESDU 82007. For bridge decks, data extracted from the literature are given for the across-wind component (that is, the rate of change of lift with wind direction) for over 30 different types of bridge. Where available, data are included on the solidity and aspect ratio of the barrier and on the turbulence levels in the original wind-tunnel tests.