Proxy observations of wind and temperature are carried out in East Queen Maud Land. The atmospheric circulation patterns are further studied by in situ observation of the diurnal wind vector variation and the upper air soundings. It was revealed that the high wind directional constancy at Mizuho Station is derived not only from the katabatic wind but also from the general synoptic pressure patterns. The katabatic wind is weakened when the westerly wind intensifies as part of the 30 to 50 day cycle synoptic pattern changes (T. YASUNARI and S. KODAMA, J. Geophys. Res., 98,13063,1992) of which the cause is still to be solved.