Air humidity and evaporation conditions in Poland in relation to atmospheric circulation patterns. The issue describing the amount of water vapour in the atmosphere and its backgrounds seems to be very important because of water vapour role among meteorological processes which are taking place within the atmosphere. The principal aim of this study is to examine the atmospheric circulation conditionings of evaporation and air humidity differentiation in Poland. Research was based on data for the period 1981-2010. The temporal and spatial differentiation of evaporation and air humidity in relation to atmospheric circulation patterns were examined by analysis of evaporation, evapotranspiration as well as specific humidity and saturation deficit values. The circulation factor was determined by a local atmospheric circulation calendar by Niedzwiedz. The results showed that atmospheric circulation is an important factor for humidity and evaporation conditions with the most significant: water vapour content and air mass temperature. Both air humidity and evaporation report temporal and spatial differentiation modified by particular synoptic situations. It is proved mainly by the extremes.