Shiverin’ Seashells! Look what happened to the water temperature at Grand Haven, Michigan:

Upwelling has caused some water temps. at Lake Michigan to take a dive.

The water temp. at Grand Haven State Park dropped from 7° from Sunday to Monday, then plummeted another 25° from Monday to Tuesday.

Here’s a look at the Grand Haven Beach Tue. evening. You can count the people on the beach on the fingers of one hand…and no one in the water. The northwest wind was coming off the water and kept air temps. at the beach in the mid 60s much of the afternoon. Look at the graph of the water temp. at the Port Sheldon buoy:

The water temp. got as warm as 76° on Sunday. Then the wind turned to the north-northeast. The wind pushed the warmer surface water toward the middle of the lake and colder water rose to the surface. The water temp. was still 71° at 3 pm on Monday, but then dropped to 55° by 10:40 pm. That’s a drop of 16° in less than 8 hours. The water will warm up when the wind turns back to the west-southwest and blows the warmer water back toward the Michigan shore.

Waves at Lake Michigan will be mostly between 6″ and 1 foot for Wednesday through Friday and we will have green flags (though we might want to consider putting up a blue flag when the water temps. are this cold!)

If you want to do some swimming, you might want to choose an inland lake, where water temps. might be considerably warmer.

You can check the beach water temps. here – updated around 10:35 am each day thru Labor Day.