We were swimming in July inside the Gulf Islands, but otherwise in open water and water temps had to be near 70. I've heard it is even warmer in Desolation Sound in the summer. The deal is that there is not the tidal exchange of the BC waters with the Pacific Ocean like there is with Puget Sound, so the water stays in the area and heats up. Water depth probably helps too. Puget Sound and the Strait of Juan de Fuca are really deep. BC waters, not as much.