Radiosonde observations of temperature and height fields for 1953-1969 have been analyzed for five tropical Pacific stations (Ponape, Guam, Yap, Eniwetok and Koror). These data have been combined to form monthly means averaged over all years and stations and annual means averaged over all stations. The analysis reveals a coherent annual variation consistent with the well-known annual temperature wave in the tropics, i.e., a tropospheric cycle with warmest temperatures around April and May, and a roughly out-of-phase lower stratospheric cycle with coldest temperatures during the period December-May. Comparing year-to-year variations in the tropospheric and lower stratospheric thermal fields, we find the out-of-phase relationship preserved. Periods of warm anomalies in the troposphere coincide with periods of cold anomalies in the stratosphere and vice versa. These observations are consistent with annual and interannual variations in the intensity of the Hadley cell circulation.