Us here in the Great White North have to deal with incredibly cold cold cold water...it is actually several degrees below freezing because of all the salt and beer runnoff in the water which allows us to have a near constant 28 degree water temp. You can see this as soon as you cross the border...the water just immediately drops in temp! You'll know when you've crossed the border because the snow starts and all the houses become igloos...A hint if you are drift diving and when you surface you don't see igloos, you have drifted into Washington state, make sure you check-in with the local authorities immediately as they will think you are trying to sneak in. I recommend carrying your passport in a ziplock just in case.
One of the Canadian gear requirements which you need to be aware of is the deco beer hanger. As part of the cold water gear list, we have found that having several bottles of beer hanging on lines at the deco/safety stop just adds to the overall enjoyment. There is nothing like cracking open an ice (and I do mean ice) cold brew and alternating between the reg and the bottle. Sure they don't teach this in most PADI classes, it is definitely a local specialty.
Seriously...diving in Vancouver is just like diving most anywhere along the Pacific coast in terms of water temps...right now we are hovering around 54 degrees on most days at the surface and mid 40's at depth.
Vancouver has at least a dozen fully equipped dive shops all over the city and surrounding areas. You can rent anything you would require. Leave your full foot fins at home...you'll need to wear neoprene boots and open heeled fins here. Most people dive dry here, those who dive wet dive with full 7mm suits, hoods, boots and gloves.
Good shore diving can be had at Whitecliffe Park and Porteau Cove in West Vancouver.
There are a number of local boat charters which will take you out if you want.
Nanaimo...1.5 hour ferry ride...has some awesome wreck diving.
I don't know where you are from or what type of diving you are used to doing...if you haven't dove in low visibility or cold water before, you might want to take a refresher lesson prior to just renting the gear and heading out. I'm sure most of the shops would be more than happy to take you out on a check-out dive to get you acclimated to the local conditions.
PM me if you want any direction in terms of shops or anything else.
Oh...and the beer deco...nah...that's what the evening surface intervals are for...I recommend Granville Island Amber Ale.
Brian