A north-northeast wind has pushed the warmer surface water along the Michigan shore back toward the middle of Lake Michigan and brought up colder water from well beneath the surface. This process is called upwelling.
Check out the Thursday morning water temperatures at Lake Michigan: Grand Haven 45° (yikes!), Saugatuck 51°, Duck Lake 53°, Hoffmaster S.P. 55°, Ludington City Beach, which is behind a breakwall, was 64°.
Here’s a graph of the water temperature at the Muskegon buoy over the last week. It shows a fairly constant water temp. between 65° and 70° until Wednesday. Then the upwelling causes the water temperature to plummet to the mid-upper 40s. Finally, with full sun and a light west wind, the water temperature has climbed back into the mid 50s.
Warmer water isn’t too far offshore. The Port Sheldon buoy showed a water temp. of 64°. The South Haven buoy had a surface water temp. of 65°. Both buoys showed waves of 8″. The wind at the Port Sheldon buoy was west at just 4 mph. Lake Michigan water temps. should be warmer for this Labor Day Weekend.
Inland lakes are going to have much water water this afternoon and tomorrow. At 1 pm (Thu.), Reeds Lake in East Grand Rapids had a water temperature of 75° and that was up 3° from the reading at sunrise, which was 72°.
ALSO: With a few notable exceptions, this has been a very comfortable month weatherwise. Today makes it 15 out of the last 18 days with high temperatures in the 70s. Twenty-One of the 31 days of August had below average temperatures. We had just 3 days that were warmer than 85° and only one day with a high temperature below 72°.
Overall, I’m expecting a very nice September with a good amount of sunshine and temperatures a bit warmer than average.