I also often read, while sitting and thawing out my frozen bones in the winter, in my hot, clean Japanese bath. When it starts cooling down, I just tap my toe on the re-heat button.
I don't think reading in a western style bath will be quite the same, since you will be lying in your own grime and the water doesn't come up to your chin
and there is no re-heat function!
I read in the bath in the sticky summer too! I don't have a pool or a jacuzzi, so what can I do! Door open, music playing, lukewarm water, large fan at full blast angled into the bathroom and a glass of iced tea. DH was at first scandalized at my reading and drinking in the bath, but he has got used to it and puts it down to my gaijin-ness
!