Variations of UHF-band scintillation occurrence with latitude, time and season over the low-latitude region of China are presented. The ratio of the mean foF2 at 20:00LT between two equinoxes, which could act as a proxy of the equinoctial asymmetry in the occurrences of scintillation, is proportional to the ratio between the maximum scintillation occurrence in the autumn equinox and in the vernal equinox. The empirical climatological model of scintillation occurrence probability was validated.