The paper presents the results of research of temporal variability of the climate elements in Poland. An attempt at preliminary assessment of the role of cloudiness and atmospheric circulation in shaping the climate of Poland was also undertaken. The spatially averaged series of climate elements from terrain of lowland Poland were used first of all. The considered data covered the second-half of the 20th century and the beginning of the 21st century, and in the case of the air temperature also 100-year series of 1901-2000. In the study analysis of correlation and simple and multiple regression was used. Significant changes of value of climate elements resulting in the circulation of warmth were demonstrated. In the second half of the 20th century non-random fluc-tuations in the radiation, sunshine and temperature appeared in spring and on average in the year. Analysis of 100-year series of air temperatures showed significant changes in all seasons except the winter. In the case of average seasonal precipitation sums and cloudiness significant changes did not appear. It was demonstrated that with the direct influence of the circulation and magnitude of cloudiness it is possible to explain up to the 80% to the variability of air temperature and precipita-tions. In the last 10-year period of the 20th century, spring and summer were “too warm” than it would result from the circulatory conditions and from cloudiness, while winter and autumn were “too cold” (even though winters were more and more warm). Tendencies of climate elements changes diversified seasonally and spatially were seen slightly in their spatial layout in the area of Poland and in certain indications of the change of the climatic regime.