The great lakes observing system has a Great Lakes Buoy Portal that provides access to data from great lakes buoys. The link first takes one to a map where buoys can be selected. For example, buoy 45028 is near Duluth, MN. The interactive graph on the page is copied here. There are other data sets which include, wind speed, wind gust, wind direction, wave height, air temp, solar radiation, along with water temp at various depths. The data download button on the page allows users to select data over various time periods. GPS coordinates of the buoy are also given. There is a lot of data here waiting to be used in a classroom.