My launch form arrived on March 24 for Wye Heritage Marine Resort, and filling one out, which includes choosing a launch date (I went for May 2) is always a cause for irrational exuberance. When I was a member of Midland Bay Sailing Club, the club launch date was always the first Saturday in May (in non-covid years), but that didn’t necessarily mean all the ice was gone. I can remember one launch when our crash boats were operating like harbour tugs, pushing ice pans out of the way of slips.
My unscientific impression of Severn Sound right now is that there is still a lot of ice out there, and that we shouldn’t be expecting a late March/early April thaw. NOAA data for Lake Huron, updated to March 25, says the ice coverage of the entire lake (Lake Huron, Georgian Bay, and the North Channel) has dipped below average, to around 20 percent of the surface. But most of Georgian Bay remains covered with an estimated 12 to 28 inches of ice.