We did the inside passage the first week of September a few years ago, and had beautiful weather.... But, you never can tell that time of year on the Inside Passage. The weather is always variable. We sailed Holland America and LOVED it. There were cultural activities on the ship and a naturalist on board. Glacier Bay was spectacular, even in a drizzle (which cleared by mid-morning). We saw lots of whales and even saw dolphins. Eagles, moose, bear... lots of critters coming down to the mouths of the rivers. Great itinerary, great cruise line.