Eileen, I'm crusing the Inner Passage on Vision of the Seas in August. From all the experienced cruisers & whatever I could find, I've learned to layer is best. I'm bringing a couple of pairs of shorts, just in case; otherwise, i plan on lighter wear for my excursions. I'm also packing a waterproof poncho, you know, those $2 type things. But I also found an waterproof poncho at Wal*Mart that i'm taking along. I have planned light pair of jeans, with a hooded sweatshirt & t-shirt under, with weaterproof slicker for my helicopter excursion. I plan on bringing my backpack, which will allow me to un-layer, hands free.
I also thought about those cargo pants, that unzip into shorts. otherwise, it's a toss-up. Again, depends on the weather.
Hope that helps!