A niche one, I know, but I also know there are a couple of other people here who like a dip. I've swum in Øresund (strait between Denmark and Sweden) on a regular basis through a second winter. The YYFY isn't really for the getting through the winter but just for finding a physical, outdoors activity I love, that puts me in nature, and that I get a huge amount back from - it's become an important part of daily life. I'm not a swimmer (I'm a rubbish swimmer in fact), I just go swimming. Mostly with a bunch of other ageing Danes.
Take care with the pinkie pulls. Easy to overdo it and tear a lumbrical.