I only cruise here in the fall season so can’t give much info beyond that.
The key to late season cruising is heat. I have a “bus heater” (works off engine heat) for underway and a Webasto furnace for anchoring out. Both work extremely well. At a marina, if I’m paying for power, I plug in my electric heater.
Set up this way, I’m sure you could continue on through the winter as it seldom freezes for too long and the water doesn’t freeze.
The water is cold right now, high 40s to mid 50’s depending on where you are.
I recorded 38 or 39 a few years back but that was in the Broughtons during December.....the latest I’ve ever stayed.
My friends here assure me they swim comfortably during summer.
I’m from a small town in NE Ontario and after retiring, do a 4,4,4 thing.
May-August at home. I trailer sail to the North channel etc
Late August-late November....cruise out here...just love it!
Late December-late April...cruise on my sailboat in the Abacos.
As such, others can give better advice on different seasons, but set up properly, I think winter, although darker and more wind/rain, could also be an amazing time to be up here.