I'm a rookie, and the water here is frigid.
I met, before the fact, another poorly-insulated guy who didn't survive a canoe-tip in Lake Ozette, IIRC, on the Olympic Peninsula. Water is about 48-50*.
I'm nowhere close to calling my self good. I basically watched one day, and tacted the next, on a Hobie on Lake Tahoe. Luckily, I figured it out.