An analysis of trends of mean monthly temperature and precipitation totals in Poland in the period 1951-2000 was carried out. Areal means of temperature and precipitation were used, averaged for 51 meteorological stations evenly distributed within Poland's borders. Sensitivity of air temperature and precipitation variations towards circulation was assessed. Circulation variations were expressed by sea-level pressure in the 52.5°N, 20°E grid point and geostrophic wind calculated from meridional (45-60°N) and latitudinal (10-30°E) pressure gradients.It was shown that the circulation factor explains up to 77% and 44% of temperature and precipitation variance respectively. Significant upward trends of temperature in March and May were detected. Also, the precipitation total in March was on the increase. The last decade of the 20th century was slightly 'too warm' in comparison with the circulation-induced temperature level, as well as with the temperature change scenario according to HadCM2 GS model.An attempt was made to evaluate the contribution of the frequency of snow cover occurrence to the temperature increase in winter, i.e. the temperature-albedo feedback.

This paper presents the results of an investigation of the variability in macro-circulation forms at the mid-tropospheric level distinguished in the Vangengeim-Girs (V-G) classification. The annual frequencies of circulation forms in the years 1891–2010 proved significant fluctuations, which provided the basis for distinguishing 7 circulation epochs. The epochs illustrate secular changes in the character of dominant forms – zonal circulation (W) prevailed at the turn of the 20th century; meridional forms E and C developed next, and zonal circulation began to dominate again after 1990.

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This paper presents the results of an investigation of the variability in macro‐circulation forms at the mid‐tropospheric level distinguished in the Vangengeim‐Girs (V‐G) classification. The number of days and of uninterrupted periods of at least 2 days (so‐called episodes) with V‐G forms were analysed based on the daily atmospheric circulation catalogue for the period 1949–2010. The average number of circulation episodes per year (~51) and their average persistence (6–9 days) were determined. When analysing the short‐term variability, the frequency of transitions between macroforms: W ↔ E, E ↔ C and W ↔ C was calculated. It was found that these sequences were random in character. Changes in average frequencies of V‐G macroforms in an annual cycle were evaluated and the seasons of dominant zonal (W) and meridional (E, C) circulation patterns distinguished. In the years 1949–2010, four circulation epochs were separated, differing in the macroform frequency quotients—fW/fE, fW/fC and fE/fC. Three epochs were meridional (until 1988) and the last one is zonal. A growing trend was observed in the number of circulation episodes, indicating an increase in the frequency of changes of circulation forms. This rise was attributed to the growing frequency of the W episodes and the decreasing number and persistence of E episodes in the last two decades of the analysed period.