The paper deals with an assessment of hydrometeorological elements like precipitation and evaporation measured and calculated in Mazovian Geographical Obserwatory at Murzynowo near Płock. Estimation of real precipitation and structure of evapotranspiration were examined based on observations carried out for 10 years. The effect of local variations of these parametres was pointed out. A program of further research to be carried out in the field of hydroclimatology was outlined.