This is just slightly off topic. Due to unimportant reasons, my usual shell wasn't available one day last week so I grabbed my cheap rain shell to use instead. It's got some venting on the back but not a ton and it doesn't portend to be made of a breathable material. It was of course dripping wet on the inside by the time I got to work. My base layer had done its job and I didn't feel damp. The outside of my fleece pullover was wet too. I also hadn't felt overly warm or hot while riding.

Nothing of this is noteworthy but what it brings home to me is how much water I'm losing when I don't even realize that I'm sweating. My jacket was dripping on the inside and that was just the sweat from my torso. It didn't include the sweat from my head or legs, or the water vapor that I exhale. It's a good reminder that I need to drink a lot of water to replace all that.

When I'm dripping with sweat in the summer, imagine how much more of it goes unnoticed since it just evaporates.