The seasonal‐latitudinal tidal structures of O, N2, and total mass density in the thermosphere for minimum and maximum levels of solar activity are investigated by using a theoretical model and accelerometer data from the Atmosphere Explorer C, D, E, and Air Force S3‐1 satellites. According to theory, oxygen variations are strongly influenced by seasonal differences in the winds, whereas N2 responds primarily to temperature, which has a different seasonal dependence than the winds. The tidal variation of total mass density is complicated by its dependence on the relative amplitudes and phases of the O and N2 variations. The net effect is that rather complicated and different seasonal‐latitudinal tidal structures are predicted to occur. Some representative theoretical profiles are presented. Theoretical height structures of diurnal amplitude and phase of O and N2 near the equator are in good agreement with recently published tidal analyses of Atmosphere Explorer E mass spectrometer data. Tidal analyses of the accelerometer data verify the shift to later times of the diurnal phase of total mass density from the equator to mid‐latitudes in the lower thermosphere as predicted by theory.