Swedish temperature and precipitation series from 1860-2001 are analysed in this report. Sweden is divided into four regions. These are defined according to the drainage basins: Gulf of Bothnia (Bv), Bothnian Sea (Bh), Proper Baltic Sea (EÖ) and Kattegatt and Skagerrak (Vh). Annual series of temperature and precipitation as well as series for the traditional seasons winter (December previous year, January, February), spring (March, April, May), summer (June, July, August) and autumn (Sep tember, October, November) are presented. All series have been homgenised and all missing values for incomplete series have been filled out by interpolation.
Generally the analyses show that Sweden has become warmer and wetter in this centennial perspective. As a rule changes and trends are larger in the two northerly regions (Bv and Bh). The increase of annual temperature amounts to 0.9° (Bv), 0.8° (Bh), 0.5° (EÖ) and 0.5° (Vh) when data from the colder period 1860-1925 is compared with the warmer period 1926-2001. Annual precipitation <luring the drier period 1860-1920 is compared with the wetter period 1921-2001. The relative changes are 23% (Bv), 15% (Bh), 7% (EÖ) and 7% (Vh). Spring temperature and winter precipitation show especially !arge mcreases.
Comparisons with runoff data indicate that evapotranspiration has become much larger. It is argued that the substantial increase of forest biomass could be one explanation and higher temperatures could be another. The increase of forest biomass leads to larger interception and then larger evaporation and as a rule also larger transpiration. The warming in spring and autumn leads to a longer active season for the vegetation.