"Winter is coming" is the motto of House Stark at the Game of Thrones fantasy by George R.R. Martin. By the way this fictional family of books and tv series has not a good destiny, but for your boat the same should be predestinated. As we are a cover maker company, it's a duty call for us write about that subject in the Autumn of the Northern Hemisphere.
It's very important to notice time by time, that UV Covers is not designed for winter use. We dedicated our covers to protect your boat against the sun during regattas and long training sessions. If you use your cover during the cold months, you has to buy a new one soon - the cold temperature destroy this light cover.
At first, we recommend to disassemble and winterize your boat and find a dry, warm place for it. But not everyone is lucky enough to do it, so if you are planning to store your boat outside, you has to choose a good wintercover to protect it as much as you can.
We are sure that there are many covermakers (or sailmakers who produce covers too) around you, so choose one, and buy a good wintercover. The key is the material, as always, there are some recommended by us too. We like Sunbrella or Weathemax, both of them are water tight, breathable and mildew resistance. Never buy a cover made from pvc, even if it's cheaper, because it's not breathable, the humidity stays inside, and it's very rigid and heavy. Better to choose something more modern.
Anyhow we are waiting for the next season, when the sun brings here summer again!