Cloudiness changes in Cracow in the 20th century

This paper presents the long-term, annual and diurnal cloud amount values for Cracow (Poland) on the basis of 95-year records. Cloud data were taken from climatological observations made at the Department of Climatology, Jagiellonian University, in the years 1906-2000. On the basis of traditional statistical methods, the following values were calculated: average cloudiness (cloud amount), number of cloudless sky occurrences for three climatological terms, daily and yearly averages, and sums of cloudless days. The cloudiness was also analysed from the point of view of its quality. For that purpose, ten specific genera of clouds adopted in the international classification were examined, taking into account the frequency of their occurrence within every month, separately for each of the climatological periods. Copyright (C) 2003 Royal Meteorological Society.