I moved my boat last year from Milwaukee, WI to Sturgeon Bay, WI in mid May. I can tell you the lake went from a mill pond one day to 60kts of wind and 10+ ft seas. We were holed up in Sheboygan for 24hrs to let the weather pass. For fun we sat in the boaters lounge and watched the waves break over the sea wall and spray over the top of the 60 ft. lighthouse on the end.
As already stated, don't under estimate just because it is called a "lake".