This paper continues the series of publications devoted to the analysis of seasonal features in the variability of submicron aerosol in the atmospheric layer up to 5 km over Western Siberia. In this paper we analyze the diurnal behavior of the vertical profile of aerosol scattering coefficient in different seasons. It is shown that in winter there are practically no regular transformations of the aerosol content during a day, however, the transport of aerosol layers by vertical motions is possible. Diurnal behavior of aerosol profile is the most pronounced in summer. Its characteristic features are the decrease of the total aerosol content in the layer under inversion (100–400 m) during nighttime and the increase of the height of mixing layer and its filling with aerosol during daytime. We did not manage to reveal any diurnal behavior of aerosol in spring and fall from the bulk of data analyzed, because of a strong day-to-day variability of all atmospheric processes.