I get this all the time - what is the best way to dress for a Mediterranean
cruise in October - November?
The answer is to layer your clothes, so you can adjust your body heat as required.
For example: wear long sleeve t-shirts under sweaters, and then top that off with a waterproof windbreaker. I guarantee you will be as warm as if you are wearing a jacket. At the most, the worst it could get is that you have to buy a sweatshirt to go underneath all of that.
By the way this also works for Alaska in summer.