Sure, it's mid-September. But Lake Superior water temperatures off the North Shore are at their highest this summer. I was in the lake with my boys for about 20 minutes just yesterday. The Federal Hudson, a big red salty, was at anchor off of Park Point. Waves were rolling in and the body surfing was fine.
A friend of mine measured the surface water off Little Marais at 62 degrees this morning. The sun is warming up the surface water, and light easterly breezes are bringing that warmer water toward the shore.
Not that water temps in the 60s are considered balmy. In fact any water temperature under 70 degrees is a threat for hypothermia within hours. But for us hardy Minnesotans, temps in the 60s are pretty decent.