We dove there a couple weekends ago, and it was absolutely awesome conditions. Visibility was 30+ feet at the St Clair River head, and into the river to the bridge. And water temps were 70-72. Sturgeon were still abundant, hanging out waiting for us!
HOWEVER, I will issue a warning. We had our vehicle parked at the west end of Canatara Park, at the gravel parking beach head access (near the tall apartment building). It was broken into and all of our valuables stolen, even our dive journals and anything else shiny,made of plastic or with a handle on it (read: ID, credit cards, purse, wallet, duffle bag, laptop bag) , whilst we were under water. Talking to Sarnia police, and local park management, break-ins have been rampant throughout Canatara Park. Be careful, don't stow valuables in your vehicle if you are parking here!