The last week before the week of Labor Day weekend wouuld be your best bet along the lakeshores because many people are back home regestering or registering kids for school, in practice for Fall sports, buying clothes for the school year, etc. Usually some openings in several of the lakeshore CGs. Avoid the week and weekend of Labor Day as there is annually 50,000 to 80,000 at the Straits are for the annual Big Mac Bridge Walk and it's a ZOO in the whole area as we'd done the 5 mile bridge walk a couple times in the past. If you know when you will be coming and where, get a reservation especially if earlier in August. There are so many parks to choose from that meet your wants! Always cool on the east side of Lake Michigan. Normal is 80 for a high daytime and 60 for a low at night in the L.P. along Lake Michigan and there's always a breeze coming off the huge lake that is like natural fresh air A/C thanks to wide very deep and cooler then the air Lake Michigan. Perfect weather and temps for play and sleeping! The big lake in the West Michigan area is always about 72-76 degrees in August and perfect for a dip or stay in for a long time. 75 and 55 in the U.P. near the lake but it's warmer on the west side of Lake Michigan buy 5-10 degrees because the air passes over more than a thousand miles of humid heated land.