Upvote:1
No need for a raincoat. Maybe a fold-able umbrella just to be sure.
Am I on the right track ?
It sounds like you could be setting yourself up for a miserable time, mitigated only by the fact that you'll have a bus to crawl back into, and plenty of tourist shops that will sell you a souvenir sweatshirt or jacket to remind you of the time you got cold.
The British Columbia coast is a temperate rain forest. Sure, summers tend to be dry, punctuated by very occasional thundershowers. September is a transition period: fine weather is still likely, but the rain starts becoming an increasing possibility.
With an itinerary that takes you to the northern coast and Banff, I would definitely pack a bit more than just summer clothes. A fleece, plus a Gore-Tex shell and waterproof shoes would make your trip more enjoyable, even if you might get lucky and not need them.
Upvote:5
Your Vancouver Island to Prince Rupert sounds like it will be by ferry, in which case having a pile jacket and/or windbreak shell (rain parka also works) will be good to have if you want to be out on deck to enjoy and photograph the sites.
These same items (pile jacket, rain parka) will come in handy in the Rockies, as it will likely be crisp at night. And while the northern Rockies enjoy great indian summer weather in September, there is always a chance of an early winter cold front coming through at that time of year, including even a chance of snow.
I would skip the umbrella in favor of the rain parka, as it does double duty for cold.