The data on the variation of the structure characteristics of the temperature field CT2 in the free atmosphere have been obtained at heights from 50 to 4000 meters. The aircraft instrument measurements were made in summer during the day and night and under different synoptic conditions above the steppe and the sea. It has been shown that under the condition of a developed convection, CT2 decreases with the height as Z−4/3. For other conditions an averaged dependence of CT2 on height was obtained. For the case of a stable stratification, the dependence of CT2 on the gradient of the potential temperature is shown. Cumulus cloudiness exerts a strong influence on the height variation of CT2. Above the sea CT2 changes little either day or night. At night above the steppe, however, CT2 increases with height. Copyright 1969 by the American Geophysical Union.