Went Snorkeling here in San Diego, CA this AM (April 1st). Water temps were very cold, 50-51F. Still there were several turtles around, and some seven gill sharks as well. I don't know how the turtles can stand such cold water. The air temps were warmer but the turtles never seem to leave the water so...
Here's a short video of the mornings swim, shot with a GoPro Hero 6 Black -
-Roger Uzun