Where I'm located, the average daytime temperature from July through October is over 90ºF. We get a few dozen days a year over 100º, and a handful of days guaranteed to be over 110º. Not unusual to have a few days in the 90's in November. We acclimate.

While I wholly appreciate erring toward the side of caution, drinking a sufficient amount to urinate every three hours, but keeping intake under 1.2L/hr, that's not a thing-- for me, where I live and ride. In +100º temperatures and single digit humidity, I'd be sweating as much as I'm drinking. Not unusual for me to take in 30oz/hr on a typical ride. I've probably emptied 2x 25oz bottles in 100 minutes ten times this month.

I'll finish this month with somewhere just over 1,000 miles. Sometimes it's plenty hot. I must be managing it alright, because I keep riding day after day.