Canadian interloper here.
For VI info, this website is the best resource:
http://www.bigwavedave.ca/Each of the main spots is listed on the forecast page, tends to be Pred1 is more optimistic, Pred2 is more pessimistic. Assuming you're talking summer, the afternoon thermals are pretty dependable in Victoria (Cook St), Sooke (Gordons), Nitinat, and Squamish. Tofino is a crap shoot, just never know....bring a big kite if you have one! Port Alberni is an interesting thermal spot on the way to Tofino, launch from a dock the local kite association built. (expert only though, downwind has no easy out)
You can click on the Wiki for details on each sailing spot.
Nitinat is a good place to check out....super consistent wind, nice forest camping out in middle of nowhere. Logging road can be a bit rough. Windfest there July10-12, races and big kite party.
Feel free to email me if you want some info closer to the date juandesooka at gmail dot com