Our coldest Gulf waters occur in late January and early February and are around 60 degrees Fahrenheit, give or take a few degrees, so maybe that would be considered "cool" or "temperate"? I also will get into swimming pools in the winter, more for a cold plunge than a swim, and I've seen these get as low as 44 degrees F. The differences in energetic effects between a long swim at 60 degrees and a quick cold plunge at 44 degrees are noteworthy, and I am now going to be paying attention to how both interact with T5T. Thanks for the tip, I'm going to look for some old hydrotherapy stuff!