Data from a network of recording precipitation gages, operated over a 5-year period on islands in Lake Michigan, provides the basis for the first monthly analysis of the relationship of lake to land precipitation conducted on the Great Lakes. Wide monthly fluctuations in lake to land relationships, previously masked by seasonal analysis using storage gages, are shown. An examination of the significance of the findings indicates that all but the largest differences are not statistically significant and that even the largest lake-land differences could possibly be attributed to gage errors.