Polar bear dips were the rage for years, but they can be dangerous to your body, even causing a heart attack if the water is too shocking.
But, cold water can be helpful for arthritis and inflammation. It reduces swelling and inflammation. How you go about that is another consideration.
I regularly do cold water dips in the wintertime, but I live in Phoenix. The water can be in the 50s. My idea of a dip is to walk down the stairs, submerge to my shoulders, and climb back out. If the water is really cold, your muscles don't work well, so you really need someone to stand by just in case.
The best way to recreate this is to take a shower - not too hot - you don't want to shock your body at contrasts, but turn it to cold before you turn it off, make a full circle and let your whole body get hit by the cold water and then climb out and bundle up.
I'm 78% Scandinavian and the rest is Highlander Scots, so my tolerance for cold and cold water is intense. When I get out of cold water, I feel invincible. My aches and pains are gone for the rest of the day. That is why I like to do it again the next day.
It may seem counter intuitive to put cold water on sore joints, but the effect is surprising.