Weather is an important factor influencing recreation activity outdoor. In great agglomerations, like Warsaw, very popular is short, one day or week-end recreation. In this case the weather is one of the reasons of enjoying or discontent with recreation. The aim of this paper is to present a bioclimatic calendar for outdoor recreation in Warsaw. The calendar bases on bioclimatic weather analysis for the period 1994-2001. The weather classification is based on the human heat balance components. The main weather feature is defined by the thermal state of an organism which is formed during the process of adaptation to actual ambient conditions. In outdoor recreation very important is intensity of solar radiation (defined in classification by absorbed solar radiation). Enjoyment or discontent with outdoor recreation depends also on the intensity of physiological strain - cold or hot - and on sultriness intensity involved by actual humidity. Additional, but very important, weather characteristic analysed in classification is precipitation and snow cover. The components of the human heat balance and other weather features were defined for every day of the studied period. BioKlima 2.0 © software package was used in this purpose. The weather characteristics were compared with the air circulation type and with air mass. It was observed clear seasonal differentiation of weather conditions in Warsaw. Very important is also great day to day variability of weather especially during early Spring and late Autumn months. From May up to September and in January-February the weather is relatively stable, with mild inter diurnal changes. Last years, the longest periods with the most favourable weather are observed in May-June and in the middle September. In the both periods continental air mass with south, south-east or east anticiclonic circulation prevail. Concentration of favourable weather out of the traditional holiday months (July-August) allows to prolong the outdoor recreation period for the habitants of Warsaw.