Where should you head? British Columbia's Strait of Georgia.
Zooming in closer, one sees the coastal upwelling and the warmer offshore. But if you look even closer (in the NE corner) was will notice some warmer water (yellows and even oranges) in the Strait of Georgia, between Vancouver Island and the BC mainland.
So why is the Strait of Georgia so warm? The topographic map of the region (below) and the depth of waters of the Strait of Georgia (also shown) give some hints. The inner Strait of Georgia is isolated from the ocean and has weak tidal currents. Furthermore, there are substantial areas where the water is shallow.
Quite suitable for swimming without a wet suit!
Talk in Port Angeles on Wed. August 17th
I will be talking in Port Angeles about the Future of the Pacific Northwest Under Global Warming at 6:30 PM on August 17th. More information here.