I notice the "water weight" gain only after very very long/hard/hilly rides. Sometimes in the heat. I also get it after eating salty, Asian food, which is the reason I no longer eat Japanese, Chinese, or Indian food more than 2-3 times a year now.
Finally back to 104 this morning. Not sure what was going on with my body, but the damage from my trip wasn't bad. I did do a lot of walking around, in addition to the hiking.