Winter freezing is about 11 days later and spring ice breakup is about 5 days earlier compared to a century ago. Some regions of Siberia have warmed by as much as 2.5°F (more than 1.4°C) in just 25 years.
Reference: Magnuson, J. et al., 2000. Historical trends in lake and river ice cover in the Northern Hemisphere. Science, 289: 1743-1746.
IPCC, 2001a. Climate Change 2001: The Scientific Basis. Intergovernmental Panel on Climate Change (IPCC) Working Group I, J.T. Houghton et al., eds. Cambridge University Press, Cambridge, UK.
