Daily estimates of the snow water equivalent (SWE) distribution for the period from 1 December through 30 April for each winter season from 1979 80 through 2002 03 were calculated for the entire Lake Superior watershed. The calculations were based on numerous groundbased daily observations collected and compiled by the National Weather Service in the United States and by the Meteorological Service of Canada in Canada. The daily estimates of SWE were then used to determine the annual accumulation and melt period characteristics of the Lake Superior watershed, along with the annual series of maximum SWE volume and the incremental accumulated SWE volume. Selected results are also shown for the individual sub-basins. Maps were also prepared of the mean SWE distributions on the 1st and 15th day of each winter month.