The study was based on daily (24 hr) depths of snow cover encompassing the periods from November to March over the years 1960/61-2009/10, collected at 40 IMGW meteorological stations, excluding mountainous regions. The essential description of temporal and spatial distribution of number of days with snow cover, including the cover with depth of at least 5 cm, and also the average depth of snow cover on the days of its occurrence, was carried out for winter months (XII-II). It was determined that over the greater area of the country snow cover lingers for 30-60 days, but only in 50-70% cases its depth exceeds 5 cm. The average depth of snow cover on the days of its occurrence ranges from 8 to 18 cm. January and February are characterised by similar numbers of days with snow cover; in February, however, its average depth in eastern regions of the country is slightly greater. During calendar winter the most snowy is the third decade of January, whereas the average depths of snow cover in the days of its lingering are the greatest in the third decade of February and also in the first ten days of March. Geographical distribution of days with snow cover and its average depth confirms severity of thermal conditions increasing from the west to the east, both in the whole winter season and in particular months. During the 50-year period of 1960/61-2009/10 a slight downward tendency of occurrence frequency and depth of snow cover is visible, but the changes are mostly insignificant. Downward trend in the number of days with snow cover, statistically significant at the level of α = 0.05, occurred mainly in December and January, whereas with snow cover exceeding 5 cm – almost only in December. A statistically significant role of atmospheric circulation, reflected by the values of NAO index, was shown in shaping variability of all the analysed features of the snow cover. Atmospheric circulation explains, depending on the region of the country, ca. 40-50% variability of days with snow cover, from 30 to 40% variability of days with snow cover exceeding 5 cm, and 25-30% changes of average snow cover depth on the days of its occurrence. The highest determination indexes, expressing the role of circulation conditions in explaining the variability of occurrence frequency and depth of snow cover between the years, were tested for January and February, and significantly lower – for December.