Partially reflected radio waves have been used to study D-region drifts in the midwinter month of July for the years 1970--72. The drifts are shown to agree well with wind estimates at similar heights obtained using meteor radar techniques. The behaviour of the drifts is consistent with a strong tidal influence, and the nature of these tides is discussed with emphasis on the phase and amplitude variations in time and height. Comparison of the monthly mean drift profiles with wind models leads to a particularly good representation of the expected zonal drift profile. No evidence is found for any anomalous winter behaviour.