Abstract: Based upon Ort’s computations, the symmetric and the antisymmetric components of the mean zonal geopotential, temperature and zonal wind with respect to the equator at 500 and 1000 hPa levels are analysed. It is found that at 500 and 1000 hPa levels these elements are, roughly speaking, symmetrically distributed with respect to the latitude all the year round, and as a whole, regardless of level and element, the absolute values and the undulation ranges of the curves of the symmetric components (hereafter referred to as symmetric curves) are much greater than the corresponding values and ranges of the curves of the antisymmetric ones (antisymmetric curves). Further, the undulation ranges of the symmetric curves, in most cases, decrease from January through July and increase from July through January. But, the corresponding undulation ranges of the antisymmetric curves, on the contrary, increase from January through July, and decrease from July through January. At 1000 hPa, there are variations similar to but not so striking as those at 500 hPa. Finally, the cause of the generation of asymmetric motion are discussed. It seems to be possible that asymmetric distribution of diadatic heating, friction and orography might be the main factors.