In a continuing study of the feasibility of using microbarom (natural infrasound) observations to define characteristics of upper air winds, we determined the seasonal mean trace velocity of microbaroms. We show that this is equal to the acoustic velocity at an upper reflection level. This velocity is the sum of the sound speed based on temperature alone and the wind speed. We determine the former from the vertical temperature profile and can thus calculate the wind speed at particular reflection levels in the stratosphere and ionosphere. Our results compare well with direct observations.