Orientations of 11,497 aeolian (wind related) features at the potential Mars Exploration Rover (MER) landing site in Isidis Planitia reflect formative winds from the northwest and are consistent with strong morning winds predicted by a regional-scale atmospheric model for Mars. Orientations of 3296 aeolian features mapped at the Terra Meridiani potential MER site suggest multidirectional wind patterns. The results for the Terra Meridiani site are consistent with gentle winds which change direction as a function of Martian season (predicted by a general circulation model) and erratic winds that occur diurnally (predicted by a regional-scale atmospheric model). Results for both sites give confidence that the predictions from the atmospheric models are basically correct when time of day and local topography are taken into account.