Of course visibility fluctuates but on average I would say it does not get black until -40m. However, there are days where you can still see people at the surface, clear as day, from -30m.
The largest swells I have dove in at the competition site, are 2 feet. And that was only once. Other than that it usually does not have swells. Except when the ferry departs you get a few seconds of 2 foot swells maybe. Temperatures in the summer time at the surface range between 15-21 degrees celcius. On average 17-19 degrees celcius.
If anybody is interested in more pictures that I have taken while freediving since September, I can send you lots or few. Mostly to do with sea life. Pictures are all from British Columbia, at Nootka Island, Tahsis, Victoria, and Ansell Pt. You can see some collections of these photos at:
http://holdyourbreath.ca/misc/20031031.html
http://holdyourbreath.ca/pics/20031217.zip
http://holdyourbreath.ca/pics/200311-11_12_13.zip
http://holdyourbreath.ca/pics/20031019-MonzimoPoint.zip
http://holdyourbreath.ca/pics/Oct.%205%2c%202003.zip
http://holdyourbreath.ca/pics/Sep.%2028%2c%202003.zip
http://holdyourbreath.ca/pics/Sep.%2025%2c%202003.zip