On the basis of the material gathered from 46 IMGW (Institute of Meteorology and Water Management) meteorological stations in the years 1971-2000 concerning monthly and 10-day period totals of hours with sunshine, the temporal and spatial distribution of probability of real insolation in Poland lasting 2, 4, 6, 8 and 10 hours per day was worked out. In the 10-day period course of average daily insolation, three periods of a decreased number of hours with sunshine can be observed in the area of Poland: the third ten-day period of May – from 0 to 1 hour, the second 10-day period of June – from 0.5 to 2 hours and the second 10-day period of July – also from 0.5 to 2 hours. The greatest probability of the occurrence of hours with sunshine is observed in the first 10-day period of August, in the first 10-day period of June and in the second 10-day period of May. The least insolation and the largest variability in the analyzed months are characteristic for December, when the probability of 10% deficiency of the multi-year average value varies in Poland from 38 to 42%. Whereas the month with the most sunshine in a major part of the country is May, in which probability of 10% deficiency of the average multi-year value varies from 28% to 34%. For the recreation and spa treatment needs the probability of gaining annual totals of real insolation was defined as 1350 and 1500 hours.