The only time I ran in to problems was when I lived in Arizona. Back in 2015 I was out on my daily 20 mile loop and it was 115 degrees. It was 130 degrees two feet off the pavement. I had three large water bottles. I was thinking about taking a fourth but decided I could "make it". About 10 miles in I had burned through two and a half bottles. Then I ran into a head wind going back. It was like having a furnace blowing 130 degree air on me.
I burned through the last half a bottle and ran out of gas with about 6 or 7 miles to go. Uh oh. I stopped sweating with about 5 miles to go. Oh damn. Then I felt myself hitting the wall with about two miles to go. I got home, but barely. I learned my lesson. NEVER ignore your gut feeling and instincts. Take more water than you think you'll need.