Most people aren’t going to believe it, but I went down the rabbit hole to see if the big wool claim is actually true: does wool get hotter when it gets wet? I talked to a wool professor, dug into the science (entropy and the second law of thermodynamics), and then built my own little test to watch it happen. In a cooler with dry wool, a humidifier, and a thermometer, I could literally see a temperature bump when moisture hit the wool—because absorbing water is an exothermic process. The catch is that the heat release only lasts a few minutes, so it’s not some magical, all-day heated jacket. From there, I moved into my standard freezer insulation tests (aquarium heating wire, thermostat, power meter) and compared wet wool against synthetic fleece. In my home testing, once everything was soaked, wool held up better—when it was carrying about three times its weight in water, it averaged about 45% warmer than the synthetic. And because I apparently make great life choices, I finished with a real-world test: jumping into a near-freezing creek wearing wool head-to-toe. Wool did surprisingly well at first, but when wind kicked up, convection and evaporation caught up to me and I had to get into dry clothes. My takeaway: wool can insulate wet, but wind protection and an emergency dry layer matter more than any “wool myth.”