In the past decade a number of MF and meteor radars have been installed in the Antarctic and Arctic. Wind measurements made with excellent height and time resolution in the 60-100 km height range allow hemispheric differences in the mean circulation, planetary wave, tidal and gravity wave activity to be investigated. It is shown that there are significant hemispheric differences in the mean circulation around the summer solstice that may be related to differences in gravity wave forcing. Wave activity observed in the Antarctic MLT shows variations in time and height that are appreciably different from that observed in the Arctic. Possible causes for these differences, including differences in wave sources and wind filtering, will be discussed.