the chills--this is the thing I find difficult. Hot water is my favorite drink. Even in summer, I spent a lot of time in baths, although when it's *very* hot with a high humidex I am quite comfortable:fasting, that is. And Water Fasting has made me more able to withstand the heat, generally. It used to make me irritable and overwhelmed.
Now I'm working on the tendancy to being cold, once the temp drops. One thing that's helped me a lot though, from where my cold tolerance and adaptability was some years ago, is going barefoot as much as possible. In sandals. I love it--even when it's cold or snowy outside. That seems to really help the body overall.