Environment Canada, Canada's national weather forecaster, provides this detailed, highly informative guide to weather patterns on the B.C. coast, including helpful tips for mariners.
|Sample page covering Kelsey Bay (Johnstone Strait) winds|
It has been "archived", so not all that easy to search for; here is the direct link to the pdf file (click to download): http://publications.gc.ca/collections/collection_2016/eccc/En56-240-3-2015-eng.pdf
IF the above link is broken, use this link to download: