I wouldn't know but I picture Lands End type styles versus the flower prints you see in the south. Easterners dress more plainly in classic styles. I am curious myself as I have considered the Canada cruise.
I realized you probably meant for the weather. It is hot in NY (90's)now but feels much cooler in Halifax. Maybe 75 and you'll need a light jacket at night. I emailed a freind in Canada and will let you know her response. Depending on where your from, the humidity can make it feel hotter.
Then you are feeling the heat that I am. I will be going your way in a month to see the Jersey shore.
My freind in Toronto says it is hot, hot hot with no end in sight. She doesn't know what Halifax is like but suggested logging onto the weather network at www.weathernetwork.ca to find out. The only problem is that it shows the temps in celcius.
I hope you have a great trip!