Sunday I worked 6+ hours building a chicken coop outside, 103, (but it's a DRY heat) I had 2 @ litre bottles of water with Liquid IV in it. I also consumed at least an additional litre of other fluids. I didn't pee until middle of dinner, but it wasn't a horrible, dark brown like I might have expected. Much less sugars than in things like gatorade, which is important for a type-1 diabetic.
For the record, I'm a "weekend warrior" when it comes to my house. I sit on my ass all day in A/C working computers. And I was in bed by around 8:00 that night