We were on a New England/Canada cruise just last month (Oct 12-23). It was cold the entire time, especially in Montreal and Quebec, but really everywhere, including the final stop in Boston. Rained off and on the entire time. Most people were in puffy jackets, vests, sweaters, boots and scarves. It was really too cold to be out on deck. On the hop-on-hop-off buses in various cities, it was FREEZING. Bundle up if you plan to do that. Open-air, cold wind. Wear something with a hood or a knit cap.
It was even cold on the ship, which surprised me. We missed one port due to the fog, it was not safe to dock.
The cruise itself was very nice, but we will never do a cold-weather cruise again. I feel that the weather really diminished the experience overall.