Expressing through intensification of extreme weather phenomena, climatic fluctuations during recent decades seem to exceed limits of typical weather variations. Increase of time and spatial variation of vegetation period duration is also observed. The goal of this paper is determination of frequency of typical and abnormal, with respect to their duration, vegetation seasons appearance in the Lublin Region. For this purpose, classification based on value of standard variation, calculated for analysed sample, was elaborated. It enabled classification of 396 seasons into following groups: A: ≤ 185 days – abnormally short vegetation season, class B: 185-200 days − short, class C: 220-232 days – average, class D: 232-248 days − long, E: > 248 days – abnormally long. Results of conducted analysis seem to suggest typical for this region variation of vegetation season duration. However, in series from the years 1990–2006, examples of increasing range of variation, exceeding up to ten days range from years 1951-1990, were noted.