Zonal wind variations corresponding to the sun's rotation period have been found by cross-spectral analysis of 10.7 cm solar flux and rocketsonde data, 25-65 km, at stations mostly near 80¿W for 1960-1976. The amplitudes of the 27-day variation have maxima near the stratospause near 25¿N and 50¿N which are nearly out of phase with each other. These results are in accordance with the land-sea heating planetary wave model recently proposed by Volland, but an alternative explanation could be direct UV heating of the upper stratosphere. Large changes are found in the 27-day variation between periods of moderate and low solar activity.