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.
Definitely layers or a light jacket. We've been a few times in October and it can be variable. Venice I needed a light jacket, Rome, long sleeve t-shirt, Villefrance, no sleeves, we then had a 5 day stay in Monaco and had a couple of days of beach weather. You never know so lots of options to layer.
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