The lakes have generally been colder, which is reflected in catching (or not) salmon.
They like 54 degree water and the past 5 or so years they have been fairly shallow throughout Lake Michigan (generally a little warmer than Huron, even though they are the same water body).
100 feet or less of water is now the norm, where in years past it was not uncommon to have to fish in 2-300 feet of water to find that 54 degree temp.
Surface water is subject to many variables. Is it sunny? Has it rained a lot? What are the wind conditions, current patterns, and so on.
The past few years before last have generally been colder on the surface, mostly due to prolonged ice coverage (which also helped against evaporation).
Regardless, the surface temp last year, according to my own measurements, never got above 68 degrees outside of the Kenosha, WI harbor mouth. We had a lot of West winds last year, and those tend to push the warmer water to the other side of the pond.