June 19 to 20 Trip - Weather Question

Sorry for making this with the weather topic at the top of this forum, but I'm just wanting to get opinions from some of the users here.

My friends and I are hoping to take a trip to Cedar Point from the 19th to the 20th. We are planning to stay at Breakers Express that night since it's cheap. Of course, we're wanting to make sure the weather for both days will be good. I'm just wondering if anyone knows how long we should wait before the weather forecast would be reliable enough to finalize plans and make reservations and what not.

If that's when you want to go, book it. The weather forecast will change 10 times between now and then.