I've experienced 115 degrees once, in Melbourne in February 2009 (the day of the fires). Ventured outside for about five minutes in mid-afternoon so I could experience what 115 degrees feels like. Five minutes was plenty....
(Hottest I've attempted to run in was 107 - coped more or less OK at the time, but it caught up with me the next morning).
Saw that Phoenix got 118, and Death Valley (where the average summer high is about 115) 126.
That's really scary how quickly you can croak.
Imagine how good 2 liters of cold water would taste when the ambient temperature is 115! But yeah, very sad to hear of people dying from the heat. Stay hydrated, everyone.
Actually, even hot water is good when it's that hot out. I remember coming back from work in Iraq and wanting water so badly that I drank nearly a 2L bottle at tea-making temperature right at the water point (stack of bottles out in the 125-degree sun). And it was soooooo good. Very strange experience.
It takes so long to adjust to such heat, and so hard to handle when the weather changes are not gradual.
I bicycled though Death Valley on August 1, 1983. We started early and stopped for a long siesta 10 AM (I think). Temperature got up to 114F in the shade; we were hanging out behind a convenience store and went in every hour or so for a cold drink. We started riding again when the temperature dropped below 110F, at 7 PM, and climbed about 2000 feet to get to a campground. The ride out the next morning over a 5000 foot pass was probably the sweatiest experience I've had in my life. As I recall, we had plenty of water -- each of us carried an extra gallon through that part of the trip (an extra 8 pounds of ballast).